Orthodontic planning systems

ABSTRACT

Systems and methods are disclosed for treating teeth to correct for malocclusions. This may be accomplished in one variation by receiving a scanned dental model of a subject&#39;s dentition, determining a treatment plan having a plurality of incremental movements for repositioning one or more teeth of the subject&#39;s dentition, and fabricating one or more aligners correlating to a first subset of the plurality of incremental movements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/386,280 filed Dec. 21, 2016, which is a continuation-in-part of U.S.patent application Ser. No. 15/230,139 filed Aug. 5, 2016, which claimsthe benefit of priority to U.S. Prov. App. 62/238,554 filed Oct. 7,2015; a continuation-in-part of U.S. patent application Ser. No.15/230,170 filed Aug. 5, 2016, which claims the benefit of priority toU.S. Prov. App. 62/238,560 filed Oct. 7, 2015; a continuation-in-part ofU.S. patent application Ser. No. 15/230,193 filed Aug. 5, 2016 (now U.S.Pat. No. 10,335,250), which claims the benefit of priority to U.S. Prov.App. 62/238,532 filed Oct. 7, 2015; a continuation-in-part of U.S.patent application Ser. No. 15/230,216 filed Aug. 5, 2016, which claimsthe benefit of priority to U.S. Prov. App. 62/238,514 filed Oct. 7,2015; and a continuation-in-part of U.S. patent application Ser. No.15/230,251 filed Aug. 5, 2016 (now U.S. Pat. No. 10,357,336), whichclaims the benefit of priority to U.S. Prov. App. 62/238,539 filed Oct.7, 2015. Each of these applications is incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

The present invention relates to methods and apparatus for computerizedorthodontics. More particularly, the present invention relates tomethods and apparatus for planning orthodontic treatments andfabricating one or more dental appliances such as retainers and alignersusing three-dimensional (3D) printing processes.

BACKGROUND OF THE INVENTION

Orthodontics is a specialty of dentistry that is concerned with thestudy and treatment of malocclusions which can result from toothirregularities, disproportionate facial skeleton relationships, or both.Orthodontics treats malocclusion through the displacement of teeth viabony remodeling and control and modification of facial growth.

This process has been traditionally accomplished by using staticmechanical force to induce bone remodeling, thereby enabling teeth tomove. In this approach, braces having an archwire interface withbrackets are affixed to each tooth. As the teeth respond to the pressureapplied via the archwire by shifting their positions, the wires areagain tightened to apply additional pressure. This widely acceptedapproach to treating malocclusions takes about twenty-four months onaverage to complete, and is used to treat a number of differentclassifications of clinical malocclusion. Treatment with braces iscomplicated by the fact that it is uncomfortable and/or painful forpatients, and the orthodontic appliances are perceived as unaesthetic,all of which creates considerable resistance to use. Further, thetreatment time cannot be shortened by increasing the force, because toohigh a force results in root resorption, as well as being more painful.The average treatment time of twenty-four months is very long, andfurther reduces usage. In fact, some estimates provide that less thanhalf of the patients who could benefit from such treatment elect topursue orthodontics.

Kesling introduced the tooth positioning appliance in 1945 as a methodof refining the final stage of orthodontic finishing after removal ofthe braces (debanding). The positioner was a one-piece pliable rubberappliance fabricated on the idealized wax set-ups for patients whosebasic treatment was complete. Kesling also predicted that certain majortooth movements could also be accomplished with a series of positionersfabricated from sequential tooth movements on the set-up as thetreatment progressed. However, this idea did not become practical untilthe advent of three-dimensional (3D) scanning and use of computers bycompanies including Align Technologies and as well as OrthoClear,ClearAligner, and ClearCorrect to provide greatly improved aestheticssince the devices are transparent.

However for traditional trim model to individual tooth, the gum geometryis lost and the fake gum is recreated, often remodeled by a technician.Hence, the gum geometry may not be accurate at first and an animation ofgum changes over time due to lack of a physical model is even harder tomodel. Such inaccurate modeling causes the resulting aligner to bemismatched resulting in devices which are too large or too smallresulting in patient discomfort.

Another problem is that without the real gum as the reference, someso-called modeled treatments cannot be achieved in reality resulting inpotential errors, e.g., a tooth movement can occur within a mis-modeledgingival, however, the tooth movement may actually be moved exteriorlyof a patient's real gingival.

Another problem of trimming and hole filling and creating an individualtooth and gum model is there is little information that can define thereal boundary of two teeth. Such trim and fill models force the boundarysurfaces to be defined even if they are arbitrary.

Depending on what boundary surface is defined, the movement can berestricted or relax, meaning some real life movement can be achieved;however, due to such inaccuracies, the modeling software is unable tomodel accurately due to models colliding into each other. This may causethe real treatment outcome to create gaps between teeth and furtherrequiring final refinements which increase cost and patientdissatisfaction. On the other hand, if the modeled movement is relax,the software may enable movements which are physically impossible inreality and this may cause the modeled device to push teeth into oneanother unable to move. This may also cause the plastic shell of thealigner to sometimes stretch so much that the shell applies anuncomfortable amount of force, which could be painful, to a patient.

Another problem of trim and hole fill is the filling of the geometrylike a real tooth, for below, the below lines are likely of boundarysurfaces modeled, such models look like a real tooth; however, suchsharp boundaries cause deeper undercuts which, once printed and thermalformed to have a plastic shell, make removal of the plastic shell fromthe printed model difficult due to the deep undercuts. To compensate forthis, a bevel object is typcially created to fill the clevis increasinginaccuracy and costs.

Another problem of trim and hole filling is the model size is too largeto communicate between the user and manufacturer thus requiring that themodel size be reduced resulting in missing model details. Theseinaccuracies could misguide professionals, e.g., the full complex modelmay not show a gap between two adjacent teeth however the reduced modelmay show one.

These 3D scanning and computerized planning treatments are cumbersomeand time consuming. Accordingly, there exists a need for an efficientand cost effective procedure for planning the orthodontic treatment of apatient.

SUMMARY OF THE INVENTION

In treating a patient to correct for one or more conditions with theirdentition, the steps of digitally scanning the patient's dentition,planning the treatment, and/or optionally fabricating the treatmentdevices, such as aligners to correct positioning of one or more teeth,may be performed directly at the provider's office.

One method for treating a subject, as described herein, may generallycomprise receiving a scanned dental model of a subject's dentition,determining a treatment plan having a plurality of incremental movementsfor repositioning one or more teeth of the subject's dentition, andfabricating one or more aligners correlating to a first subset of theplurality of incremental movements.

In one variation, this may further comprise reassessing the subject'sdentition after a predetermined period of time to monitor therepositioning of the one or more teeth.

In another variation, this may further comprise fabricating one or moreadditional aligners correlating to a second subset of the plurality ofincremental movements.

In another variation, this may further comprise treating the one or moreteeth via a non-aligner corrective measure.

In another variation, this may further comprise receiving an input fromthe subject relating to the treatment plan.

In another variation, determining the treatment plan may furthercomprise applying a label to one or more teeth within the dental model,simulating a rolling ball process along an exterior of the one or moreteeth and gums within the dental model, determining a boundary betweeneach of the one or more teeth and gums based on a path or trajectory ofthe rolling ball process, assigning a hard or soft region to each of theone or more teeth and gums within the dental model, and moving aposition of the one or more teeth within the dental model to correct formalocclusions in developing a treatment plan.

In another variation, determining the treatment plan may furthercomprise determining a movement for a plurality of digital tooth modelsin the dental model for correcting the malocclusions via a toothmovement manager module, assigning a sphere of influence on each of thetooth models to set a proximity distance between each tooth model via acollision manager module, monitoring an actual state of each tooth ofthe subject, comparing the actual state of each tooth against anexpected state of each tooth model via a tooth manager module, andadjusting the movement of one or more teeth based on a comparison of theactual state and the expected state if a deviation is detected.

In another variation, fabricating one or more aligners may furthercomprise generating a free-form structure having a lattice structurewhich matches at least part of a surface of the dentition, wherein thelattice structure defines a plurality of open spaces such that thefree-form structure is at least partially transparent, and manufacturingthe lattice structure by impregnating or covering a coating into or uponthe lattice structure such that the oral appliance is formed.

In another variation, fabricating one or more aligners may furthercomprise fabricating a support structure which corresponds to an outersurface of the dentition, forming one or more oral appliances upon anexterior surface of the support structure such that an interior of theone or more oral appliances conform to the dentition, and removing thesupport structure from the interior of the one or more oral appliances.

In another variation, fabricating one or more aligners may furthercomprise calculating a rule-based cutting loop path on the model fordetermining a path for trimming a mold replicating the patient'sdentition, applying a drape wall from the cutting loop on the model toreduce a complexity of the model, determining a position of a cuttinginstrument relative to the mold for trimming the mold, generating acomputer numerical control code based on the drape wall and position ofthe cutting instrument, and fabricating the mold based on the generatedcomputer numerical control code.

Systems and methods are disclosed for treating teeth to correct formalocclusions. This may be accomplished by applying a series of labelsto a digital dental model and applying a rolling ball process toidentify tooth boundaries separating one tooth from a neighboring tooth.The rolling ball process may also be used to determine the crown/gummargin. The user may further assign regions to the dental model toindicate hard regions (hard regions have a criteria where they cannotchange their shape) and soft regions (soft regions have a criteria wherethey can deform with an attached hard region). With the dental modellabeled and defined, the user may then generate a treatment plan formoving the labeled and defined tooth or teeth relative to one another tocorrect for any malocclusions. Upon approval of the treatment plan, aseries of 3D printed dental appliances or aligners to be worn in seriesby the patient may be fabricated to ultimately move the tooth or teethto a desired position.

One method for planning a treatment for correcting malocclusions maygenerally comprise receiving a scanned dental model of a subject'sdentition and then applying a label to one or more teeth within thedental model. The rolling ball process may be simulated along anexterior of the one or more teeth and gums within the dental model fordetermining a boundary between each of the one or more teeth and gumsbased on a path or trajectory of the rolling ball process. The hard orsoft regions may be assigned to each of the one or more teeth and gumswithin the dental model and a position of the one or more teeth withinthe dental model may be moved by the user to correct for malocclusionsin developing a treatment plan. Once approved (e.g., by the patientand/or user), one or more prostheses or aligners may be fabricated tomove the one or more teeth according to the treatment plan.

Moving a position of the one or more teeth in developing the treatmentplan generally comprises morphing a new dental model from the dentalmodel. As described, the one or more prostheses or aligners may befabricated, e.g., via 3D printing the one or more aligners, so that theentire process of may be accomplished in a single visit by the subjectto a dental office.

In another example for planning a treatment for correctingmalocclusions, the method may generally comprise directly scanning asubject's dentition to create a digitized dental model and having theuser apply a label to one or more teeth within the dental model. Thesimulated ball may be rolled digitally along an exterior of the one ormore teeth and gums within the dental model for determining a boundarybetween each of the one or more teeth and gums based on a path ortrajectory of the rolling ball process. The hard region may be assignedto each of the one or more teeth and a soft region may be similarlyassigned to gums within the dental model. Then a position of the one ormore teeth may be moved within the dental model to correct formalocclusions in developing a treatment plan.

As described, once the treatment plan has been approved (e.g., by thepatient and/or user), one or more prostheses or aligners may befabricated to move the one or more teeth according to the treatment planand the entire process of may be accomplished in a single visit by thesubject to a dental office.

Advantages of the system may include one or more of the following. Thesystem allows close control by the treating professional at each stageby allowing specific movements from one stage to the next stage. In oneexample, it is desirable in some settings to synchronize the movementand operation of the individual tooth models to have a few tooth modelsoperate in a choreographed manner as dictated by a treatingprofessional. Having this choreographed movement is not typicallypossible through manual control where the tooth models move randomly andindependently. The present control method and/or system are ideal foruse in moving a number of tooth models and to provide synchronized toothmovement. Such a method may be non-swarming to avoid any collisionsbetween the teeth and to also avoid the appearance of merely randommovements, at least in some applications. Rather, it is desirable forthe tooth models to each react safely to environmental conditions suchas changes in bone structure and soft tissue during group tooth movementof choreographed tooth models.

The system is also provided for controlling tooth movement of aplurality of biological objects (tooth models). The system includes aplurality of tooth models each including computer code controlling itsmovement. The system also includes a tooth movement control system(TMCS) with a processor executing a dental manager module and withmemory scoring a different tooth movement plan for each of the toothmodels. In practice, the tooth movement plans are stored in the memoryof each of the tooth models (e.g., a different tooth movement plan foreach tooth model). Then, during tooth movement operation, each of thelocal control modules independently controls the tooth model to executethe tooth movement plan stored in the memory of the tooth model.

In some cases, the local control module of each of the tooth modelsoperates to periodically compare a present position of the tooth modelwith the tooth movement plan and, based on the comparing, modifyingcontrol of the tooth model. In these cases, modifying of the control mayinclude altering a tooth movement speed or selecting a new way point forthe tooth model in the tooth movement plan as a target. In other cases,the local control of each of the tooth models may operate to detectanother one of the tooth models within a safety envelope about the toothmodel and, in response, communicate a collision warning message to thedetected one of the tooth models to cause the detected one of the toothmodels to alter its course to move out of the safety envelope. In somespecific implementations, the tooth models are teeth, and the localcontrol module of each of the tooth models operates to detect pitch androll of the tooth and, when the pitch or the roll exceeds a predefinedmaximum, switches operations of the tooth to a safe operating mode.

The description also teaches a tooth movement control method. In thiscontrol method, an initial step may be to receive a tooth movement planunique to each of the teeth for a plurality of teeth. A next step mayinvolve concurrently operating the teeth to execute the tooth movementplans. The method further includes providing a communications channelbetween pairs of the teeth with a first one of the teeth detecting asecond one of the teeth in a predefined space proximal to the first oneof the teeth. The method also includes, with the first one of the teeth,transmitting a message to the second tooth over the communicationchannel between the first and second teeth causing the second tooth tochange position to avoid collision.

In some implementations of the method, the tooth movement plans mayinclude a plurality of way points for each of the teeth. In suchimplementations, the method may further include, during the operating ofthe teeth to execute the tooth movement plans, adjusting tooth movementspeed or course of one of the teeth based on comparison of a presentposition and one of the way points. The tooth movement plans may furtherinclude an elapsed time period for each of the way points, and then, theadjusting of the tooth movement speed or course may be performed whenthe elapsed time is exceeded by the one of the teeth.

In some implementations of the method, the teeth movements aredecomposed to different movement metrics, e.g. a tooth movement can bedecomposed to tip, rotation around long axis, bodily movement, etc. Theartificial intelligence network, usually a neural network is built, suchnetwork having different neurons and weights can be adjusted, wheretreated cases are the learning set of such neural network. By inputtingeach case and adjusting the network weights to make the network morepredictable to the treatment outcome, when a new case comes, thedesigned movement may be run through the network and an ideal and morepredictable movement design is achieved. The more training cases areprovided, the more robust network can be achieved.

In one embodiment, each tooth executes rules that as a group conforms toone or more of the following goals or objectives:

-   -   1. Adherence to Andrews' Six Keys To Occlusion;    -   2. Root cannot move more than 0.5 mm per month;    -   3. Conform to a U or V formation;    -   4. Open the bite;    -   5. No interproximal reduction;    -   6. Avoid moving any implant tooth;    -   7. Define sub-group of teeth that move together as a unit.

The system allows close control by the treating professional at eachstage by allowing specific movements from one stage to the next stage.In one example, it is desirable in some settings to synchronize themovement and operation of the tooth models to have tooth models operatein a choreographed manner as dictated by a treating professional, whichis not possible through manual control where the tooth models moverandomly and independently.

The present control method and/or system may be ideal for use in movinga number of tooth models and to provide synchronized tooth movement.Such a method would be non-swarming since it is desirable to avoidcollisions and to also avoid the appearance of merely random movement(at least in some applications) of the tooth models. Rather, it isdesirable for the tooth models to each react safely to environmentalconditions such as changes in bone structure and soft tissue duringgroup tooth movement of choreographed tooth models.

Turning now to fabricating free-form structures including oralappliances or aligners, one method for fabricating an oral appliance maygenerally comprise capturing a three-dimensional representation of adentition of a subject and generating a free-form structure having alattice structure which matches at least part of a surface of thedentition, wherein the lattice structure defines a plurality of openspaces such that the free-form structure is at least partiallytransparent. The lattice structure may then be manufactured byimpregnating or covering a coating into or upon the lattice structuresuch that the oral appliance is formed.

One or more oral appliances may thus be manufactured where eachsubsequent oral appliance is configured to impart a movement of one ormore teeth of the subject and is intended to be worn by the subject tocorrect for any malocclusions.

Generally, the oral appliance may comprise the lattice structure whichis configured to match at least part of a surface of a dentition of thesubject, wherein the lattice structure defines a plurality of openspaces such that the free-form structure is at least partiallytransparent. A coating may impregnate or cover into or upon the latticestructure and at least one dental attachment structure may be formed aspart of the lattice structure, wherein the dental attachment structureis located in proximity to one or more teeth to be moved.

The system provides free-form structures fitting the surface of a bodypart, which are at least partially made by additive manufacturing. Thefree-form structures may comprise a basic structure which includes alattice structure and a coating material provided thereon. The latticestructure may be impregnated in and/or enclosed by the coating materialwhich may include, e.g., polymeric or ceramic materials and metals.Furthermore, the coating material may include different regions ofvarying thickness or other features incorporated into the material. Thepolymer may include a number of different types, e.g., silicone,polyurethane, polyepoxide, polyamides, or blends thereof, etc. Inalternative embodiments, the lattice structure may be impregnated inand/or enclosed by a foamed solid.

In certain embodiments, the lattice structure may be defined by aplurality of unit cells with a size between, e.g., 1 and 20 mm. In otherembodiments, the lattice structure may be provided with varying unitcell geometries having cell varying dimensions and/or varying structuredensities. In other embodiments, the lattice structure may be comprisedof at least two separate lattice structure parts movably connected toeach other and integrated into the structure.

In certain embodiments, the free-form structure may further include oneor more external and/or internal sensors (e.g. pressure and/ortemperature sensors) and/or one or more external and/or internal markers(e.g. position markers). Such markers can be read externally todetermine current tooth movement to help the practitioner in decidingfuture movement adjustments, if needed.

In certain embodiments, the free-form structure may further include oneor more agents disposed externally and/or internally such as variouschemicals or drugs, e.g., tooth whitening materials, insulin which canbe slowly delivered orally to a diabetic patient, etc. Such chemicals,drugs, or medicine can also be incorporated to loosen up the gums and/ortendons to enable teeth move faster, wound treatments, etc.

In certain embodiments, the free-form structure may further comprise oneor more external and/or internal locators so that, when such a device ismisplaced, the user can use a mobile computer to detect the location andfind the device. The locator can include any number of devices, e.g.,magnets, wireless proximity detectors, optical proximity detectors, etc.

The free-form structures can also be further configured to havedifferent stiffness values in different regions of the structureutilizing a number of different configurations.

In one aspect, systems and methods are disclosed for fabricating one ormore oral appliances by capturing a three dimensional representation ofa body part of a subject such as the dentition and creating a removableinner support structure. One or more of the oral appliances may befabricated directly upon one or more corresponding support structures.Once the oral appliance has been completed, the inner support structuremay be removed to leave the dental appliance that fits over one or moreteeth for correcting malocclusions in the dentition.

One method for fabricating an oral appliance may generally comprisecapturing a three dimensional representation of a dentition of asubject, fabricating a support structure which corresponds to an outersurface of the dentition, forming one or more oral appliances upon anexterior surface of the support structure such that an interior of theone or more oral appliances conform to the dentition, and removing thesupport structure from the interior of the one or more oral appliances.

The one or more oral appliances may be formed in a sequence configuredto move one or more teeth of the subject to correct for malocclusions.Moreover, the support structure may be fabricated from a first materialand the one or more oral appliances may be fabricated from a secondmaterial different from the first material.

Generally, the oral appliance assembly may comprise the supportstructure having an exterior surface which corresponds to an outersurface of the dentition of the subject, wherein the support structureis fabricated from a first material, and the oral appliance formed uponthe exterior surface of the support structure via three dimensionalprinting such that an interior of the formed oral appliance conforms tothe dentition of the subject, wherein the oral appliance is fabricatedfrom a second material different from the first material.

The support structure is generally removable from the interior of theformed oral appliance such that the oral appliance is positionable uponthe dentition. Furthermore, a plurality of oral appliances may be formedwhere each oral appliance is formed in a sequence configured to move oneor more teeth of the subject to correct for malocclusions. Accordingly,each oral appliance may be formed upon a plurality of correspondingsupport structures.

The structures according to the present invention can have a differentstiffness in different parts of the structure and can be madetransparent, even though they are made at least partially via additivemanufacturing. The free-form structures according to the presentinvention can further be made as a single part, and may further compriseinternal or external sensors.

Systems and methods are disclosed for cutting and trimming dental moldsand oral appliances by receiving a digital model of teeth, determining acutting loop path and applying a drape wall to the cutting loop togenerate a simplified tooth base in a dental mold having an inner archcurve and an outer arch curve. The oral appliance may be formed on thedental mold and a cutter may be applied using a single sweeping motionacross the inner and outer arch curves.

The system enables an easy way to cut and trim tooth models. The systemallows close control by the treating professional at each stage byallowing specific movements from one stage to the next stage. The systemcan form aligners quickly and efficiently due to the drape wallsimplification. The CNC machines can manufacture each shell as a customdevice for many stages of tooth movement. The mold can be cut/trimmedusing inexpensive 2D cutting machines, if needed. Additionally, theresulting oral appliances (aligners, shells, etc.) can be removed fromthe positive mold with minimal force, reducing risk of shell tear fromexcessive removal force.

Generally, one embodiment for a method of forming an oral appliance maycomprise receiving a digital model of a patient's dentition, calculatinga rule-based cutting loop path on the model for determining a path fortrimming a mold replicating the patient's dentition, applying a drapewall from the cutting loop on the model to reduce a complexity of themodel, determining a position of a cutting instrument relative to themold for trimming the mold, generating a computer numerical control codebased on the drape wall and position of the cutting instrument, andfabricating the mold based on the generated computer numerical controlcode.

Another embodiment for a method of forming an oral appliance maygenerally comprise receiving a digital model of a patient's dentition,calculating a rule-based cutting loop path on the model for determininga path for trimming a mold replicating the patient's dentition, applyinga drape wall from the cutting loop on the model to reduce a complexityof the model, determining a predetermined height of a base of the model,generating a computer numerical control code of the model, andfabricating the mold based on the generated computer numerical controlcode.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of the figures of specific embodiments of theinvention is merely exemplary in nature and is not intended to limit thepresent teachings, their application or uses. Throughout the drawings,corresponding reference numerals indicate like or corresponding partsand features.

FIG. 1A shows an exemplary process for scanning the patient's dentition,treatment planning, and then fabricating one or more aligners foreffecting patient treatment.

FIG. 1B shows an example of a flow diagram illustrating how an initialtreatment planning may be reassessed and additional treatment optionsmay be generated or considered during additional treatment planning.

FIG. 2A shows a flow diagram of one exemplary method for a toothmodeling system.

FIG. 2B shows another exemplary method for adjusting a treatment processwhen results deviate from the initial treatment plan.

FIG. 3A shows one exemplary process for planning a treatment process increating a model file.

FIGS. 3B to 3D show various views of a tooth to be digitally manipulatedvia moving widgets displayed upon the tooth of interest.

FIG. 4 shows one exemplary labeling system in planning the treatmentprocess.

FIG. 5 shows a rolling or dropping ball method for detecting the toothboundary during treatment planning.

FIG. 6A shows how the rolling or dropping ball follows the clevis ofteeth.

FIG. 6B shows how the ball trajectory path can be used to find themargin lines between adjacent teeth.

FIG. 6C show how once the margins are defined, the entire dental modelmay be separated into two portions to detect a tooth boundary orgeometry.

FIG. 7 shows an exemplary mass-spring model which may be used to modelthe teeth and gums as an interconnected system.

FIG. 8 shows an example of how the treatment planning may be implementedwith respect to the patient.

FIG. 9 is functional block diagram of a multiple tooth model systemuseful for implementing the tooth movement control techniques describedherein.

FIG. 10 is a functional schematic or block diagram of a system for usein providing tooth movement management or tooth movement control overtwo or more moving objects such as tooth models.

FIG. 11A shows an exemplary process for fabricating a dental applianceusing a lattice structure.

FIG. 11B shows an exemplary process for fabricating a dental appliancewith varying material thickness using a lattice structure.

FIG. 12A shows a perspective view of an example of a basic structureformed into a bottom half and a top half for a dental applianceutilizing a lattice structure which may be used in a 3D printingprocess.

FIG. 12B shows a detail exemplary view of the openings in a latticestructure.

FIG. 12C shows an exemplary end view of a lattice structure havingseveral reticulated layers.

FIG. 12D shows an exemplary end view of a lattice structure havingregions comprised only of the coating material.

FIG. 12E shows a detail perspective view of a lattice structure andcoating having a feature such as an extension formed from the surface.

FIG. 12F shows a detail perspective view of a lattice structure andcoating having different regions with varying unit cell geometries.

FIG. 12G shows a detail perspective view of a lattice structure andcoating having different regions formed with different thicknesses.

FIG. 12H shows an exemplary end view of a lattice structure havingregions with a coating on a single side.

FIG. 12I shows a perspective view of an aligner having at least oneadditional component integrated.

FIG. 12J shows an exemplary end view of a lattice structure a hinge orother movable mechanism integrated along the lattice.

FIG. 12K shows a perspective view of an aligner having one or more(internal) channels integrated.

FIG. 13 shows a perspective detail view of a portion of an alignerhaving an area that is machined to have a relatively thicker materialportion to accept an elastic.

FIGS. 14A and 14B illustrate a variation of a free-form dental appliancestructure having a relatively rigid lattice structure and one or morefeatures for use as a dental appliance or retainer.

FIG. 14C shows a partial cross-sectional view of a suction featurefabricated to adhere to one or more particular teeth.

FIG. 14D shows a perspective view of a portion of the aligner havingregions configured to facilitate eating or talking by the patient.

FIG. 14E shows a perspective view of a portion of the aligner havingdifferent portions fabricated to have different areas of varyingfriction.

FIG. 14F shows a perspective view of a portion of the aligner having aparticulate coating.

FIGS. 15A to 15D show various views of examples of lattice structuressuitable for forming dental appliances.

FIG. 16 shows an exemplary 3D printed dental structure with a supportpositioned within the structure.

FIGS. 17A and 17B show cross-sectional side views of various embodimentsof a 3D printed dental structure having an inner and outer layer.

FIG. 18 shows another embodiment of a 3D printed dental structure with apocket defined within.

FIG. 19 shows yet another embodiment with a ball like materialpositioned between two tooth portions.

FIG. 20 shows an exemplary model having a slot for supporting metalwires therein.

FIG. 21 shows an exemplary process for adjusting the thickness of the 3Dprinted oral appliance.

FIG. 22 shows an exemplary process for determining the thickness of anoral appliance based on physical simulation.

FIG. 23 shows an exemplary process for fabricating an oral appliance.

FIGS. 24 and 25 show side views of an exemplary process of defining atrim line between opposed dots on a digital model of the oral appliance.

FIG. 26 shows a top view of an oral appliance formed with one or moreslots to facilitate manufacturing.

FIG. 27 shows a side view of an oral appliance mounted on a base formanufacturing.

FIG. 28 shows a side view of the oral appliance and some of thedirections that the appliance may be translated and/or rotated tofacilitate trimming of the appliance.

FIG. 29 shows a top view of a cutting device which may be used to trimthe oral appliance and some of the directions that the cutting devicemay be articulated.

FIG. 30 shows a top view of an oral appliance and a cutting device formanufacturing.

FIG. 31 shows a side view of an oral appliance secured to a base forprocessing.

FIG. 32 shows an exemplary process for laser cutting a physical mold forthe oral appliance.

FIG. 33 shows a side view of an oral appliance formed with a toolingcavity to facilitate articulation of the oral appliance.

FIG. 34 shows a side view of another oral appliance having a regionformed to facilitate removal of the appliance via a stream of air orgas.

FIG. 35 shows an exemplary process for facilitating removal of the oralappliance.

FIG. 36 shows a side view of another oral appliance having a cavityformed to facilitate its removal via a wedged removal member.

FIG. 37 shows an exemplary process for facilitating removal of the oralappliance via the wedged removal member.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with respect to particularembodiments but the invention is not limited thereto but only by theclaims. Any reference signs in the claims shall not be construed aslimiting the scope thereof.

As used herein, the singular forms “a”, “an”, and “the” include bothsingular and plural referents unless the context clearly dictatesotherwise.

The terms “comprising”, “comprises” and “comprised of” as used hereinare synonymous with “including”, “includes” or “containing”, “contains”,and are inclusive or open-ended and do not exclude additional,non-recited members, elements or method steps.

The terms “comprising”, “comprises” and “comprised of” when referring torecited members, elements or method steps also include embodiments which“consist of” said recited members, elements or method steps.

Furthermore, the terms first, second, third and the like in thedescription and in the claims, are used for distinguishing betweensimilar elements and not necessarily for describing a sequential orchronological order, unless specified. It is to be understood that theterms so used are interchangeable under appropriate circumstances andthat the embodiments of the invention described herein are capable ofoperation in other sequences than described or illustrated herein.

The term “about” as used herein when referring to a measurable valuesuch as a parameter, an amount, a temporal duration, and the like, ismeant to encompass variations of +/−10% or less, preferably +/−5% orless, more preferably +/−1% or less, and still more preferably +/−0.1%or less of and from the specified value, insofar such variations areappropriate to perform in the disclosed invention. It is to beunderstood that the value to which the modifier “about” refers is itselfalso specifically, and preferably, disclosed.

The recitation of numerical ranges by endpoints includes all numbers andfractions subsumed within the respective ranges, as well as the recitedendpoints.

All documents cited in the present specification are hereby incorporatedby reference in their entirety.

Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, definitions for the terms used inthe description are included to better appreciate the teaching of thepresent invention. The terms or definitions used herein are providedsolely to aid in the understanding of the invention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to a person skilled in the art from this disclosure, in one ormore embodiments. Furthermore, while some embodiments described hereininclude some but not other features included in other embodiments,combinations of features of different embodiments are meant to be withinthe scope of the invention, and form different embodiments, as would beunderstood by those in the art. For example, in the following claims,any of the claimed embodiments can be used in any combination.

In treating a patient to correct for one or more conditions with theirdentition, the steps of digitally scanning the patient's dentition,planning the treatment, and/or optionally fabricating the treatmentdevices, such as aligners to correct positioning of one or more teeth,may be performed directly at the provider's office.

As shown in the exemplary process of FIG. 1A, the step of scanning thepatient's dentition 10 may be performed using a number of differentprocesses, as described in further detail herein. With the resultingdigital images of the patient's dentition, the treatment planning 18 tocorrect for the positioning, misalignment, malocclusion, etc. of any oneor more teeth may be performed using any of the processes describedherein. Conventional treatment planning typically creates an entiretreatment plan starting with the initial positioning of the patient'sdentition and formulating a treatment based on a stepped realignment ofthe dentition. This stepped realignment is then used to create an entirearray of aligners starting with an initial aligner and ending with afinal aligner for use through the entire treatment process.

However, the treatment planning 18 and fabrication process 20 describedherein may be performed on a variable treatment path. That is, while theinitial treatment planning 18 may be based upon the initial positioningof the patient's dentition, the step-by-step process for subsequenttreatments is variable such that the final treatment step is notpre-determined. Rather, the alignment of the dentition is determined atintermediate steps in which the patient may (or may not) come back tothe practitioner's office for reassessments and potentially new scansand aligners for one or more intermediate treatment steps. In thismanner, additional aligners or other treatment processes may be createdduring each visit to the practitioner by the patient. Hence, the entiretreatment process is created as the treatment progresses thus leading tothe treatment planning 18 and fabrication process 20 as an iterativeprocess rather than an entire treatment sequence pre-determined at thetreatment outset.

An example is shown in the flow diagram of FIG. 1B which illustrates howthe initial treatment planning 30 may be performed and one or moreinitial aligners may be fabricated for use by the patient. After initialtreatment, the patient may be assessed 32 and additional treatmentoptions 34 may be generated or considered during additional treatmentplanning. Based on the assessment 32, various treatment options may beconsidered and the patient re-assessed 36, 38, for example, after apredetermined period of time. The assessment may be formed by thepractitioner based on the progress or lack of progress of moving thepatient's tooth or teeth to a desired position. Additionally, thepatient may also collaborate with the practitioner to provide their ownassessments, thoughts, etc. so that the practitioner may consider notonly the physiological data but also the collaboration provided by thepatient.

Depending on which treatment option was pursued, additional treatmentoptions 40, 46 may be considered and their corresponding outcomere-assessed 42, 44, 48, 50 again depending on which treatment option waspursued. Depending upon the assessment and, if needed, the patient mayagain be provided with treatment options 52, 54, 56, 58 and the processmay be continued at predetermined intervals until the desired outcome isreached. Because the treatment process is not predetermined from thestart to the end of the entire treatment and the treatment options maybe varied, the aligners may be fabricated with only a few at a time.This also provides flexibility to the practitioner to alter thetreatment mid-course without having an entire array of pre-fabricatedaligners un-used.

Returning to FIG. 1A, the fabrication process 20 itself may beaccomplished through different methods. In one example, the model of thepartially corrected patient dentition may be formed as a positive mold,e.g., via a 3D printing mold 22 and corresponding aligner or alignersmay be thermal formed 24 upon the positive molds. In another example,the one or more aligners may be directly formed, e.g., direct 3Dprinting 26. In either case, the resulting one or more aligners 28 maybe formed for use by the patient.

Scanning the Dentition

Obtaining a digital model of the patient's dentition for facilitatingthe treatment planning may be accomplished in a number of differentways. The patient may have their dentition scanned at another locationand forwarded to the treatment provider or their dentition may bescanned directly at the treatment provider's location. In either case,the patient's dentition may be digitally scanned through any number ofsuitable scanning devices. For example, the patient may have theirdentition (including teeth, soft tissue, or both) scanned by an MRIscanner, X-ray machine, intra-oral scanner, etc. The resulting scannedimages may be saved or uploaded to a computer system and used togenerate a digital image of the teeth which may be used for planning thetreatment to correct for the positioning, misalignment, malocclusion,etc. of any one or more teeth. Alternatively, the patient's dentitionmay be cast to obtain an impression which may then be used to create apositive mold. The resulting positive mold reflecting the patient'sdentition may then be scanned to obtain the corresponding digital image.

Treatment Planning

The treatment planning process may be implemented after receiving andanalyzing the scanned dental model of a patient's dentition. The scanneddental model may be accordingly processed to enable the development of atreatment plan which can be readily implemented for fabricating one ormore positioners for use in effecting sequential tooth movements.

FIG. 2A shows an exemplary overall tooth modeling process which may beused in planning the treatment for correcting malocclusions in apatient. The process shown may involve initially acquiring a patient'sdental record 110 in the form of, e.g., lower arch and/or upper arch CADfiles, intra oral photos, X-rays or 3D CT scans, etc. The lower archand/or upper arch CAD files may be created, for instance, through anumber of different methods, such as taking lower and upper impressionsof the patient's dentition, X-rays, etc.

Once the dental records are acquired, the lower arch and upper archrelationship may be imported or calculated 112 for registration by oneor more computing devices and a flexible dental anatomy model may beauto created 114 by one or more processors located locally in proximityto where the patient is treated, e.g., dental office, or remotely fromthe patient location. Once the dental anatomy model has been digitallycreated and confirmed to fit and that the arch model can open and closeas expected, one or more possible treatments may be created in real-timechairside of the patient 116 and the one or more treatment options maybe may be shown and/or discussed with the patient chairside 118 wheresimulations of the treatment options may also be shown and/or discussedfor potentially altering the treatment plan as needed. The simulationsof treatment options may be displayed to the patient using any number ofelectronic display methods.

Following the discussion of the treatment options with the patient, thetreatment plan (with any alterations) may be used to generatemanufacturing files for the fabrication machinery 120, e.g., 3D printingmachines, thermal forming, laser sintering, etc. Because the resultingone or more positioners may be fabricated locally in proximity to thepatient (e.g., dental office, clinic, nearby facility, etc.) the one ormore resulting positioners for use by the patient may be fabricatedlocally allowing for the patient to try on the one or more positioners122 during the same visit.

Such a treatment plan may have particular advantages over conventionalplanning and treatment plans including one or more of the following:

-   exact treatment may be developed right way and discussed with the    patient in real time;-   practitioner has full control of the treatment plan options which    are easy to create;-   real gum modeling may be implemented;-   one or more positioners may be fabricated locally allowing the    patient to try-on during the same visit;-   easy to incorporate other treatment methods, e.g. indirect bonding    bracket, rubber bands, hooks, retainers, etc. in combination with    one or more positioners.

Even in the event that a treatment plan has been developed andimplemented for a patient, as shown and described for FIG. 2A, theactual progress of the tooth movement(s) may not correspond to thetreatment plan or the actual progress may begin to deviate from thetreatment plan. Because of this variability, not all of the positionersor aligners may be fabricated at the start of the treatment but thepositioners may instead be fabricated in preset stages for use by thepatient until a subsequent visit to the practitioner, e.g., every sixweeks, where a new set of positioners may be fabricated for subsequenttreatments. FIG. 2B shows an example of this staged treatment planningwhere the treatment plan may be adjusted during the actual treatmentaccording to any changes or deviations by the patient's progress.Furthermore, the implementation of a staged treatment planning processalso enables the practitioner to employ other devices or methods (e.g.,brackets, wires, etc.) for correcting malocclusions in addition to or inplace of the fabricated positioners.

As described above, the patient's dentition may be scanned or otherwiserecorded to capture a three-dimensional (3D) representation 130 of thepatient's dentition and an initial treatment plan may be determined 132for forming one or more dental appliances 134 for correcting anymalocclusions. Rather than fabricating the dental appliances for theentire treatment process, a staged number of appliances may be initiallyfabricated for use by the patient until their subsequent visit. Thepractitioner may evaluate the patient's tooth movement progress atsubsequent visits according to the treatment plan 136 as originallydeveloped. In determining whether the patient's tooth movement progressdiffers from the treatment plan 138, the practitioner may compare thetreatment plan with the patient's actual tooth movement(s) to determinewhether they correlate with one another. Such a comparison may be donein a number of ways, e.g., visually by the practitioner or the patient'sdentition may be scanned again and the captured 3D representation of thetreated dentition may be digitally compared against the treatment plan.

If the system determines that the actual tooth movement progress doesnot differ from the treatment plan, the tooth movement may be continuedaccording to the treatment plan 140 without alteration and an additionalnumber of positioners may be fabricated for use by the patient until thesubsequent visit. Provided that the next visit and subsequent visittracks according to the original treatment plan, the additional set ofpositioners may be fabricated until the treatment has been completed andthe malocclusions corrected.

However, if during any one of the evaluations the practitionerdetermines that the actual tooth movement does differ from the treatmentplan, the practitioner may be alerted of the deviation 142 by thesystem. The treatment plan may then be automatically adjusted by thesystem for the next set of dental appliances or positioners 144 tocorrect for the deviations so that the newly fabricated positionersprovide for a better fit to the patient's dentition and is responsive tocorrecting for the deviations. At subsequent visits, the tooth movementwith the altered treatment plan may be evaluated 136 to determinewhether the tooth movement differs from the altered treatment plan 138and if no deviation is detected, treatment may be continued but if adeviation is detected, the practitioner may be alerted of the deviationand the altered treatment plan again be adjusted accordingly. Thisprocess may be continued until the detected tooth movements appear tofollow the treatment plans.

Because the system is programmed to alert the practitioner of anydeviations for particular teeth, the practitioner is able to determineif the patient is non-compliant with wearing the positioner and/orwhether any there are any problematic tooth movements which thepractitioner can then flag for continuing treatment or whether otherdevices or methods, e.g., conventional braces, may be employed forparticularly problematic teeth. The treatment plan (as any subsequenttreatment plans) may be shared with others through any number of methodsand/or devices.

In importing or calculating the relationship between the lower arch andupper arch 112, the digital models of the lower arch and/or upper archmay be loaded 150, e.g., into a computer, as shown in the flow diagramof FIG. 3. Additionally, as part of creating a dental anatomy model 114,the bite registration between the lower arch and upper arch may be setand mounted on a virtual articulator 152 and the user may then drag anddrop the tooth ID to an area of interest 154 for correcting themalocclusion. In digitally modeling the margin between the crown andgum, the process may assign regions that are designated as “hard” and“soft” 156 with conditions set where a region with a “hard” designationcannot change its shape and a region with a “soft” designation is ableto be deformed with an attached “hard” region.

Additionally, any number of moving widgets may be defined at variousregions or locations 158 for facilitating the movement and control ofthe regions. For instance, the process may allow for defining movingwidgets: mesial/distal, lingual/facial, vertical, etc. Moreover, theuser may be enabled to control the widgets and calculate a morphed newmodel 160 in developing a treatment plan. Once the treatment plan hasbeen completed, the plan may be exported, e.g., to a 3D printeracceptable model file 162, for use in manufacturing one or more of thepositioners or for manufacturing molds for subsequent thermal forming.

These moving widgets may be view-based widgets which facilitatemanipulation of the model in developing the treatment plan. When themodel is displayed in a particular view, the manipulation widgetsdisplayed may be programmed to allow for model manipulation only in theparticular view which is displayed. For example, FIG. 3B shows alingual/facial view with the moving widget 164 displayed upon the toothT of interest to be moved for treatment planning. With the tooth T ofinterest displayed, e.g., upon a screen or monitor, the movement widget164 may be displayed upon or over the particular tooth T. The movementprovided by the widget 164 may move the digital model of the tooth T invarious translational and/or rotational movements. FIG. 3C shows how thetooth T shown in a vertical/apical view may have the moving widget 164′displayed upon the tooth T for digitally manipulating the tooth T andFIG. 3D shows a mesial/distal view of the tooth T with moving widget164″ similarly displayed for treatment planning.

Additionally and/or optionally, each tooth may be displayed either inits native color or alternatively colored, e.g., yellow or red, toindicate to the practitioner that a proposed corresponding movement isdifficult or unlikely to be achieved thereby providing the practitionerguidance to find alternatives treatments.

In preparing the scanned image of the patient's dentition for treatmentplanning, the digital model may be initially labeled. For example, FIG.4 shows an example of a labeling system where the scanned dentitionmodel 170 may be seen. A number of labels 172, in this example a totalof 16 labels (e.g., 1 to 16 or 17-32 depending on the arch), may beinitially laid out alongside the model 170 allowing for the user toassign a label to a targeted tooth by, e.g., dragging and dropping alabel to a particular tooth. In this example, while the label is draggedit may remain visible but after being assigned by being dropped upon aparticular tooth, the tooth may change to indicate that it has beenlabeled. For instance, the tooth may be changed in color to indicatethat it is now labeled, e.g., from the color red to indicate anunassigned tooth to the color white to indicate the tooth being labeled.

In facilitating the treatment planning, moving widgets may be defined onthe digital model 158 and controlled 160 accordingly, as discussedabove. As shown in FIG. 4, one example is illustrated of a moving widgetwhere a center vertex 174 indicated as a circle may be defined along themodel 170. The selected vertex related mesh should be form a singleconnected region to provide a way to read the list. The center vertex174 is indicated as a center while a second vertex 176 may be definedrelative to the center vertex 174 such that the first arm 178 definedbetween may point directly outside the tooth surface in the lingual tobuccal direction. A third vertex 180 may be defined relative to thecenter vertex 174 such that the second arm 182 defined between pointsalong the center of the teeth in the mesial to distal direction. Thefirst arm 178 and second arm 182 need not be perpendicular to oneanother.

The moving widget may be applied only to teeth which are labeled (andhence teeth which may be moved in the model) and may provide a way toread and orient the direction of the arms 178, 182 and their origin. Themoving widget may be hidden from view from the user when not in use.

Once the tooth labeled and a small set of mesh are identified, a dropball algorithm may be used to detect the gum margin and teeth margin.FIG. 5 shows an exemplary process for digitally detecting andidentifying a tooth boundary or geometry from the scanned dentition ofthe patient by simulating a rolling or dropping ball 194 to detect theboundary of the tooth 190 and gum 192. The ball 194 may be simulated toroll from a high energy state 196, e.g., at the tooth crown, to a lowresting state 198, e.g., at bottom of the tooth. As the ball 194′ rollsdown longitude, there is a bump 200 which tip up at the margin areabetween the tooth and gum where the inflection changes. By looking atthese areas and at the correct curvature changes, the margin line can bedetected. This method can also detect occlusal teeth margins and gummargins as well.

However, to detect the side margin between two adjacent teeth, therolling ball algorithm may be used, as described, to follow the knownmargin lines of the teeth but in-between the adjacent teeth, theboundary of the teeth may be extrapolated. For instance, FIG. 6A showsan example where the rolling ball 194 may be rolled to follow theoutline of adjacent teeth 212, 214. The region 218 in-between the teethmay be generally inaccessible to the ball 194 but the ball willnaturally follow the clevis 216 of the teeth. Hence, the extrapolatedtrajectory path 220, 222 that the rolling ball 194 would follow betweenthe teeth 212, 214 can be used to find the margin lines between adjacentteeth 212, 214 even though the ball 194 may not access the region 218in-between, as illustrated in FIG. 6B.

As shown in FIG. 6C, once the margins are defined over the model, theentire dental model may be separated into two parts: a hard crownsurface and a soft gum surface. In one embodiment, the “hard” surface224, 226 may be considered a rigid surface which moves in an integralpart and maintains its shape whiling moving. The “soft” surface 228, 230may be attached to the “hard” surface 224, 226 and may deform based onthe movements of the hard surface 224, 226. Such a movement does notchange the overall topological structure of the dental model, hence thefinished model by default is watertight, which fits a 3D printerrequirement.

This deviates from the traditional separate model to individual toothmodel, which requires models to be trimmed and then capped (holefilling) to make it watertight. Due to the complexity of scanned toothgeometry, such trim and hole filling is a very complex process.

FIG. 7 shows an exemplary mass-spring model 240 which may be applied tothe dental model in determining tooth movement. It is generallydesirable in some settings to synchronize the movement and operation ofthe individual tooth models to have a few tooth models operate in achoreographed manner as dictated by a treating professional. Having thischoreographed movement is not typically possible through manual controlwhere the tooth models move randomly and independently. The presentcontrol method and/or system are ideal for use in moving a number oftooth models and to provide synchronized tooth movement. Such a methodmay be non-swarming to avoid any collisions between the teeth and toalso avoid the appearance of merely random movements, at least in someapplications. Rather, it is desirable for the tooth models to each reactsafely to environmental conditions such as changes in bone structure andsoft tissue during group tooth movement of choreographed tooth models.

The mass-spring model 240 may be constrained to be directly attached toa hard surface and the model 240 can be stretched or compressed. Anynumber of algorithms can be used to calculate its shape, e.g.mass-spring model, in one implementation of mass-spring model 240, twonodes may be modeled as mass points connected by a parallel circuit of aspring and a damper. In this approach, the body is modeled as a set ofpoint masses (nodes) connected by ideal weightless elastic springsobeying some variant of Hooke's law. These nodes may either derive fromthe edges of a two-dimensional polygonal mesh representation of thesurface of the object, or from a three-dimensional network of nodes andedges modeling the internal structure of the object (or even aone-dimensional system of links, if for example a rope or hair strand isbeing simulated). Additional springs between nodes can be added, or theforce law of the springs modified, to achieve desired effects. Havingthe dental model constrained as a mass-spring model 240 helps tosynchronize the movement and operation of the individual tooth models tohave a few tooth models operate in a choreographed manner.

Applying Newton's second law to the point masses including the forcesapplied by the springs and any external forces (due to contact, gravity,etc.) gives a system of differential equations for the motion of thenodes, which is solved by standard numerical schemes for solvingordinary differential equations. Rendering of a three-dimensionalmass-spring lattice is often done using free-form deformation, in whichthe rendered mesh is embedded in the lattice and distorted to conform tothe shape of the lattice as it evolves. Assuming all point masses equalto zero, one can obtain the stretched grid method aimed at severalengineering problems solution relative to the elastic grid behavior.

Another way to calculate the model 240 is using finite element analysis(FEA) models where the “soft” parts of the model are separated intosmaller FEA elements, e.g., tetrahedron or cube elements, and some ofthe element surfaces may be attached to “hard” portions as so calledboundary condition in FEA analysis while “soft” portions (gum portions)may be assigned various material properties such as Young's Modulusconsistent with gum portions. While the hard parts are moving, theboundary condition may change and hence all the elements based on itsconnections to its neighboring elements may form large matrices. Bysolving such matrices, each individual element shape and locations maybe calculated to give a calculated gum deformation during treatment.

In one embodiment, the body may be modeled as a three-dimensionalelastic continuum by breaking it into a large number of solid elementswhich fit together, and for which a model of the material may be solvedfor determining the stresses and strains in each element. The elementsare typically tetrahedral, the nodes being the vertices of thetetrahedra (tetrahedralize a three dimensional region bounded by apolygon mesh into tetrahedra, similarly to how a two-dimensional polygonmay be triangulated into triangles). The strain (which measures thelocal deformation of the points of the material from their rest state)may be quantified by the strain tensor. The stress (which measures thelocal forces per-unit area in all directions acting on the material) maybe quantified by the Cauchy stress tensor. Given the current localstrain, the local stress can be computed via the generalized form ofHooke's law. The equation of motion of the element nodes may be obtainedby integrating the stress field over each element and relating this, viaNewton's second law, to the node accelerations.

An energy minimization method can be used, which is motivated byvariational principles and the physics of surfaces, which dictate that aconstrained surface will assume the shape which minimizes the totalenergy of deformation (analogous to a soap bubble).

Expressing the energy of a surface in terms of its local deformation(the energy is due to a combination of stretching and bending), thelocal force on the surface is given by differentiating the energy withrespect to position, yielding an equation of motion which can be solvedin the standard ways.

Shape matching can be used where penalty forces or constraints areapplied to the model to drive it towards its original shape (e.g., thematerial behaves as if it has shape memory). To conserve momentum therotation of the body must be estimated properly, for example via polardecomposition. To approximate finite element simulation, shape matchingcan be applied to three dimensional lattices and multiple shape matchingconstraints blended.

Deformation can also be handled by a traditional rigid-body physicsengine, modeling the soft-body motion using a network of multiple rigidbodies connected by constraints, and using, for example, matrix-paletteskinning to generate a surface mesh for rendering. This is the approachused for deformable objects in Havok Destruction.

The processes, computer readable medium and systems described herein maybe performed on various types of hardware, such as computer systems 250,as shown in FIG. 8. Such computer systems 250 may include a bus or othercommunication mechanism for communicating information and a processorcoupled with the bus for processing information. A computer system 250may have a main memory, such as a random access memory or other dynamicstorage device, coupled to the bus. The main memory may be used to storeinstructions and temporary variables. The computer system 250 may alsoinclude a read-only memory or other static storage device coupled to thebus for storing static information and instructions.

The computer system 250 may also be coupled to a display, such as a CRTor LCD monitor 254. Input devices 256 may also be coupled to thecomputer system 250. These input devices 256 may include a mouse, atrackball, cursor direction keys, etc. for use by the user 258. Computersystems 250 described herein may include, but are not limited to, thecomputer 252, display 254, scanner/3D printer 260, and/or input devices256. Each computer system 250 may be implemented using one or morephysical computers or computer systems or portions thereof. Theinstructions executed by the computer system 250 may also be read infrom a computer-readable medium. The computer-readable medium may be aCD, DVD, optical or magnetic disk, laserdisc, carrier wave, or any othermedium that is readable by the computer system 250. In some embodiments,hardwired circuitry may be used in place of or in combination withsoftware instructions executed by the processor.

As will be apparent, the features and attributes of the specificembodiments disclosed herein may be combined in different ways to formadditional embodiments, all of which fall within the scope of thepresent disclosure.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. Thus, such conditional language is not generally intended toimply that features, elements and/or states are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or states are included or are to beperformed in any particular embodiment.

Any process descriptions, elements, or blocks in the flow diagramsdescribed herein and/or depicted in the attached figures should beunderstood as potentially representing modules, segments, or portions ofcode which include one or more executable instructions for implementingspecific logical functions or steps in the process. Alternateimplementations are included within the scope of the embodimentsdescribed herein in which elements or functions may be deleted, executedout of order from that shown or discussed, including substantiallyconcurrently or in reverse order, depending on the functionalityinvolved, as would be understood by those skilled in the art.

All of the methods and processes described herein may be embodied in,and fully automated via, software code modules executed by one or moregeneral purpose computers or processors, such as those computer systemsdescribed herein. The code modules may be stored in any type ofcomputer-readable medium or other computer storage device. Some or allof the methods may alternatively be embodied in specialized computerhardware.

It should be emphasized that many variations and modifications may bemade to the herein-described embodiments, the elements of which are tobe understood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

Aside from processes for modeling the individual teeth and tissues,there are additional control methods and systems (or multiple toothmodel systems incorporating such control methods/systems) for use incontrolling a flock of tooth models numbering from 1 to 32. That is, themethod treats groups of teeth as a flock (e.g., such as a flock of birdswhich travel collectively) in planning the movements of the teeth fortreatments to correct for malocclusions.

Briefly, the control method uses hierarchical-based supervisory controlwith multicasting techniques along with adaptive logic including onboardor local control modules provided on each tooth model to adjust toothmovement paths to safely avoid collisions based on communication withnearby tooth models. The result of the described control of the multipletooth models in an oral cavity is a flocking behavior in which the toothmodels appear to move in a synchronized manner with movements that areneither completely independent nor completely centrally controlled.

The control method in planning a treatment may be implemented in asystem 310 generally having several components including a toothmovement manager module 312, collision manager module 314, and toothmanager module 316 for controlling the movement of tooth models. Thesecomponents or aspects of the control method/system 310 communicate witha computer system 318 and are described below and as shown in FIG. 9.

FIG. 9 illustrates a tooth controller/computer or teeth movement controlsystem (TMCS) 310 that may be used to control tooth movement in a safeand repeatable manner.

The system 310 includes tooth movement manager module 312 whichcommunicates with the computer system 318 (which includes one or moreprocessors) upon which the digital tooth models of a patient's teeth 320reside. As shown, the digital tooth models on the computer system 318are configured for an inter-tooth model or tooth communications and, asexplained herein, this intercommunication allows the teeth 320 to safelychange its path for correcting malocclusions by determining whetherparticular teeth 322, 324 are in conflicting movement pathways to avoidcollisions while generally remaining on a predefined tooth movementpath.

During runtimes, the tooth movement manager 312 is programmed to sendcommands to the computer system 318 to monitor and maintain performanceand quality and also to monitor safety of the teeth to be moved. Thetooth movement manager 312 is further programmed to upload toothmovement requirements to the computer system 318 during downtimes, e.g.,non-runtimes.

A second module, collision manager module 314, may be programmed tointeract with the computer system 318 to handle collisions between teethto be moved. The collision manager 314 may be programmed to perform thefollowing logic: (a) calculate a “sphere of influence” on each toothmodel, e.g., determine a proximity distance between each tooth model totrigger a collision event and if a tooth model enters this sphere ofinfluence around a specific tooth model, a collision event is triggered;(b) determine through a nearest neighbor algorithm whether a possibleconflicting pathway will occur; and (c) present to the operator on auser interface provided on the computer system 318 (e.g., via a monitordevice) that a potential pathway conflict will occur between any twoteeth. The collision module 314 may store the tooth movement paths inmemory, e.g., within computer system 318.

Another module includes a tooth manager module 316 which is programmedto monitor the expected state and the actual state of each of the teeth320. For example, the module 316 may compare a present position ortraveling speed of, e.g., tooth 324, with its expected state which maybe defined by a tooth movement path or a choreographed and/ortime-synchronized movement of tooth models such as with a treatmentanimation. Based on this monitoring, the tooth manager module 316 maymake adjustments such as using the following priorities: localization(e.g., position of the a tooth model with respect to another tooth modelor teeth); environment (e.g., adjusting for bone conditions or thelike); safety (e.g., returning the tooth model to a safe location oroperating mode if the tooth model or other tooth models are notoperating as expected); show performance (e.g., adjusting position,speed, or other operating parameters to meet show needs); tooth status;and operator convince/performance needs.

As discussed above, the tooth manager module 316, collision module 314,and tooth movement manager 312 are configured to work together toprovide flocking-type control. In use, the inter-tooth modelcommunications allows operational data to flow or spread hierarchicallyamong each of the tooth models rather than relying uponcentralized/tooth movement control alone. In other words, the toothmanager module 316 provides a level of centralized control or centrallogic that acts to control the movement of the tooth models/teeth suchas by providing tooth movement paths provided by the tooth movementmanager module 312 and/or making real-time adjustments based on acomparison of expected state and actual state (or for safety reasons) asprovided by the collision manager module 314. With regard to inter-toothmodel communications, it may be useful to note the following: (a) someunits may be designated as master nodes talking with the tooth manager316; and (b) the master nodes may operate to send out in-tooth movementcalculated information or commands to remaining tooth models.

The movement of the individual tooth models and control of the modelsare not swarm-based in part because swarming-based tooth models cancollide with one another or have an inherent lack of safety. The system310 is designed to avoid random movements as the digital tooth modelsare subject to moving as a flock having synchronized movements among theindividual tooth models. However, the inter-tooth model communicationsas processed and generated by the local control modules allow for eachtooth model to react safely to environment conditions such asdirection-changing and the presence/movement of neighboring teeth ascrossing tooth movement paths is allowed in the system 310. In otherwords, the onboard logic acts to control the tooth movements so as toavoid collisions while attempting to stay generally on the toothmovement path.

FIG. 10 illustrates a general system (or a tooth movement managementcontrol system) 330 generally for use in managing or controlling toothmodels to provide for synchronized tooth movement by simulating flockingmovement of the teeth to correct for malocclusions. As shown, atreatment plan for moving the one or more teeth 332 to correct formalocclusions may be initially developed. The system may includecomponents used to perform off-line activity and used to perform on-lineactivity. The off-line activity may include designing or selecting atreatment concept or choreographed movement for a plurality of toothmodels to achieve a particular effect or perform a task(s). The toothmovement concept (e.g., digital data stored in memory or the like) maybe processed with a computer system 318 or other device.

Each tooth to be used may be modeled as a particle to simulate movementof the one or more teeth as a flock of teeth 334 (such as a flock ofbirds), as described herein. Accordingly, each digitized tooth model maybe configured by the computer system 318 to define a three-dimensionalspace, such as a three-dimensional sphere with a predefined diameter,around each tooth model. This three-dimensional sphere may be used todefine a safety envelope for the tooth model or flying object to reducethe risk of a collision between to individual tooth models. Forinstance, each of the tooth models may be created and create andchoreographed by the system 318 to avoid collisions with one another andwhere two or more tooth models are prohibited from having their safetyenvelopes intersect or overlap as the tooth models move along theirtooth movement paths.

The created tooth movement plan for the multiple tooth models is thenexported to memory of computer system 318 or other devices forprocessing with this “treatment illustration” typically including a fileper each tooth model. Each of these files is processed to generate realworld coordinates for each tooth model to be achieved over time duringan animation or performance of a choreographed task(s) to illustrate themovement of teeth 336, e.g., on a display, to the practitioner and/orpatient. This processing creates individual tooth movement plans foreach tooth model, and such processing or generating of the toothmovement plans may include processing the modeled animation based onspecific logistical requirements. For example, these requirements may bemodified, as needed, e.g., is the dental space the same size and shapeas in the simulation and, if not, modification may be useful to changeor set real world coordinates for one or more of the tooth models.

Once the treatment plan has been approved 338, the treatment plan may beused to fabricate one or more dental appliances or positioners using,e.g., three-dimensional printing 340, locally at the location of thetreatment planning.

In planning the simulation of the movement of the individual toothmodels as a flock of teeth 334 for working up a treatment plan, thetooth models may be manipulated using the TMCS 310 described herein. Thelogistical requirements may also include setting a tooth movement truthfor the venue and adding safe or “home” points where each tooth can besafely positioned such as at the beginning and end of a treatmentprocess or when a safety over-ride is imparted (e.g., “stop”). Atreatment planning management component may he considered a componentthat translates central treatment plan controller commands where toothactions are sent to the tooth management component either throughscripts (e.g., data files), real time computer messages, and/or hardwaretriggers.

The tooth movement plans are provided to the TMCS 310, as describedabove, and the system further includes a number of tooth models shown inthe form of teeth in this example. The teeth may be organized intogroups or sets with a set shown to include, e.g., two molars, a setincluding one molars, and a set including cuspid teeth, among others.These sets may act or function together, at least for a portion of ananimation or tooth movement path, to perform a particular display ortask.

In other cases, all of the teeth may be considered part of large setthat moves as a flock or otherwise has its movements time-synchronizedand/or choreographed by tooth movement plans. A tooth in the group cancommunicate with its nearby or neighboring teeth so as to determinetheir presence, to determine their proximity, and when needed, toprocess the tooth movement plan, determine neighbor position, and otherenvironmental data to modify their tooth movement plan to avoidcollision and/or communicate with the neighboring tooth to instruct itto move or otherwise change its tooth movement plan/movement to avoidcollision.

During pre-tooth movement, an operator uses the TMCS to load a toothmovement plan onto each tooth model. During a tooth movement sequence,the TMCS and its tooth manager module 316 acts to run the tooth movementplan previously loaded on the tooth model. During the tooth treatment,the TMCS actively monitors safety and a practitioner can initiate a TMCSuser action. More typically, though, the TMCS monitors the operation ofall the tooth models in the flock by processing telemetry data providedby each of the tooth models provided by each tooth model. In someembodiments, the tooth manager module 316 has software/logic thatcompares the actual state of each tooth model against the expected stateat that particular time for the tooth model according to the presentlyenacted tooth movement plan.

After the “go” or start signal is issued by the tooth managermodule/TMCS upon an operator input, the TMCS along with the localcontrol software/hardware on each tooth model work to safely perform thepreloaded tooth movement plan/show. As discussed above, the controlmethod and system combines centralized, control (e.g., to allow manualoverride for safety or other reasons during a show/tooth movement-basedtask) with smart tooth models to more effectively provide flock-typemovement of the tooth models. In other words, the tooth models may eachbe given a particular tooth movement plan that they work towards overtime (e.g., during an animation period) while attempting to respond tothe unexpected presence of another tooth model within or near to theirsafety window (or safe operating envelope surrounding each tooth modelsuch as a sphere of, e.g., 1 to 3 mm or the like, in which no othertooth model typically will travel to avoid collisions).

During operations, the TMCS is used to trigger each of the tooth modelsto begin their stored tooth movement plan starting from an initial startpoint, e.g., each tooth model may be placed at differing startingpoints. In some cases after the “go” is received by a tooth model, eachtooth model uses its local control module (or othersoftware/programming) to attempt to follow the tooth movement plan butwith no time constraints. In other words, the tooth movement plan maydefine a series of points or way points for the tooth model. In theseembodiments, the tooth model is controlled in a relatively fluid mannerand not tied to accomplishing specified movements in a certain amount oftime, e.g., the tooth movement plan does not require the tooth model tobe at a particular location at a particular time after the go signal isreceived hence allowing for planning flexibility.

In some implementations, the tooth movement plan may be built upassuming that each tooth model travels at a preset and constant toothmovement speed. This tooth movement speed may be set independently foreach tooth model or may be the same (or within a relatively small range)for each of the tooth models. In other cases, though, the local controlmodule may be adapted to adjust the tooth movement speed to suit theconditions in the mouth of the patient. The bone hardness may bedetermined at the tooth model with the local control module and/or viaoptical sensors for detecting actual tooth movement (rather than plannedmovement) may be provided by the TMCS to each of the tooth model. Insome cases, flock control is preferred such that each tooth model hasits speeds adjusted commonly, e.g., each tooth model runs at similartooth movement speeds while moving in a similar direction so as toappear to have synchronized and non-random movement.

In some embodiment, each tooth model may act independently to try tocontinue to follow its own tooth movement plan. Each tooth movement planmay differ in that each tooth model begins at a different start point orhome and moves toward its first way point. To this end, each tooth modelis equipped, as needed, to determine its present three dimensionalposition along with its present height above the gum line. The localcontrol module uses this present position data to determine or modify,if necessary, its present direction or heading to continue to movetoward the next way point in its tooth movement plan. This may involvechanging it course and also its angle to reach the desired height at theway point.

An operator may take steps to manually override a particular one of themany tooth models to provide better control of that tooth model. Forexample, the tooth control module of the TMCS 310 may operate to comparean expected position of the tooth model with its actual position(provided via back end channel in its telemetry or other data). Awarning may be provided in a graphical user interface (GUI) that thetooth model is trending off course or is outside an accepted tolerancefor reaching its next way point.

For example, the GUI may show properly operating and positioned toothmodels in a first color (e.g., green) and tooth models that are offcourse or out of position by a safe amount in a second color (e.g.,yellow) and tooth models outside of a safe envelope in a third color(e.g., red). The red/unsafe tooth models may be handled automatically ormanually to cause them to enter a safe mode of operation (e.g., returnto home). The yellow tooth models that are operating outside of desiredconditions may be manually operated to try to assist them in returningto their tooth movement path such as by manually changing speed,direction, angle of attack, or the like to more quickly bring the toothmodel to a desired way point. After manual operations are complete, thecontrol may be returned from the TMCS to the local control module forlocal control of the tooth model based on the tooth movement plan storedin its memory. The TMCS may be configured to evaluate collision issuesand execute collision avoidance commands to preserve show quality (e.g.,tooth movement performance) in degrading mouth conditions.

In other embodiments, a local control module of a tooth model mayoperate to adjust the tooth movement plan during tooth movement tobetter react to environmental conditions (such as toothache ortemporarily gum discomfort, at least temporarily, off course). Forexample, a tooth movement plan may provide a time relative to a starttime (when “go” was signaled by file TMCS to the tooth models) to reacheach of its way points on the tooth movement plan. One embodiment maycall for a tooth model to determine a distance to a next tooth model andits present estimated time of arrival. If the time of arrival is notwithin a window about a preset/goal arrival time, the local controlmodule may act to increase the tooth movement speed of the tooth modelsuch as by increasing the rate of rotation of a tooth.

Likewise, if the tooth model is moving too quickly, the tooth model'slocal, control module may act to slow the tooth movement speed. In thismanner, the movement of the tooth models may remain better synchronizedto provide a flock control.

In other cases, though, the local control module of the tooth or othertooth models act to determine whether a way point was reached within apredefined time window with the tooth movement plan defining times forbeing at each way point relative to a start/go time. If not (e.g., thetooth model did not reach a way point at time “X” plus an allowabledelay), the local control module may act to modify the tooth movementplan by directing the tooth model to skip the next way point and movedirectly to the way point within the mouth.

For example, a tooth movement plan may include way points A to Z. If alocal control module determines that a predefined time window for waypoint C was not achieve, the local control module may skip or remove waypoint D from the tooth movement plan and cause the tooth model to take adirection/course (e.g., a straight line or other predefined path) to waypoint E. In this way, the tooth movement speed is maintained (e.g., alltooth models are moved at the same speed) while allowing the tooth modelto “catch up” if they fall behind in their tooth movement plan (e.g.,defining a set of way points to pass through or nearby within apredefined time period that may correspond with a time to perform ashow/display or perform a task with the teeth).

With regard to safety and monitoring of operations, each tooth model maystore a definition of a geofence that defines an outer perimeter (and aninner area in some cases) or boundary of a geographical area. The toothmodels local control module compares the present position determined forthe tooth model during a tooth movement and compares this position tothe geofence. If this boundary is crossed (or is being approached suchas within a preset distance from the geofence), the local control modulemay act to promptly return the tooth model back within the geofenceboundaries. In other cases, the tooth model may be switched into a safeoperating mode and this may cause the tooth model to return to a homeposition.

Further, regarding safe tooth model operations, some embodiments oftooth movement control may involve configuring the tooth models to havetooth model-to-tooth model (or tooth-to-tooth) communications to avoidcollisions without reliance upon the TMCS to intervene. Each tooth modelmay use its local control module to operate on an ongoing basis todetect when another tooth model comes within a predefined distance fromthe tooth model such as within a sphere of 1 to 3 mm or the like. Thefirst tooth model to detect such a condition (or both tooth models if atie) generates a collision warning message and transmits this message tothe offending/nearby tooth model to alter its course or present positionto move out of the first tooth models dental space. For example, thetooth model receiving such a collision warning message may store anevasive action in its memory and initiate this action (a fixed movementsuch as angling to the right or left a preset angle). The evasion may betaken for a preset time period and then the tooth model may return tofollowing its tooth movement plan (e.g., recalculate a course to thenext way point from its new present location or the like).

In another example, the tooth models local control module monitors thepresent orientation of the tooth model and if the orientation is outsidean acceptable range (e.g., tip or rotate exceeds 320 degrees or the likefor a tooth) or if the bodily movement is too much, the local controlmodule may also act to enter the tooth model into a safe operating mode(before or after attempting to correct the operating problem).

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the spirit and scope of the invention,as hereinafter claimed.

As will be apparent, the features and attributes of the specificembodiments disclosed herein may be combined in different ways to formadditional embodiments, all of which fall within the scope of thepresent disclosure.

Fabricating One or More Aligners

The system described herein is related to the fabrication of dentalappliances such as retainers and aligners using three-dimensional (3D)printing processes. The appliance may be formed to have hollow shapeswith complex geometries using tiny cells known as lattice structures.Topology optimization can be used to assist in the efficient blending ofsolid-lattice structures with smooth transitional material volume.Lattice performance can be studied under tension, compression, shear,flexion, torsion, and fatigue life.

Free-form lattice structures are provided herein, which fit at leastpart of the surface, e.g. external contour, of a body part.Specifically, the embodiments described may utilize free-form latticestructures for forming or fabricating appliances which are designed forplacement or positioning upon the external surfaces of a patient'sdentition for correcting one or more malocclusions. The free-formstructure is at least partially fabricated by additive manufacturingtechniques and utilizes a basic structure comprised of a latticestructure. The lattice structure may ensure and/or contribute to afree-form structure having a defined rigidity and the lattice structuremay also ensure optimal coverage on the dentition by a coating materialwhich may be provided on the lattice structure. The lattice structure isat least partly covered by, impregnated in, and/or enclosed by thecoating material. Furthermore, embodiments of the lattice structure cancontribute to the transparency of the structure.

The term “free-form lattice structure”, as used herein, refers to astructure having an irregular and/or asymmetrical flowing shape orcontour, more particularly fitting at least part of the contour of oneor more body parts. Thus, in particular embodiments, the free-formstructure may be a free-form surface. A free-form surface refers to an(essentially) two-dimensional shape contained in a three-dimensionalgeometric space. Indeed, as detailed herein, such a surface can beconsidered as essentially two-dimensional in that it has limitedthickness, but may nevertheless to some degree have a varying thickness.As it comprises a lattice structure rigidly set to mimic a certain shapeit forms a three-dimensional structure.

Typically, the free-form structure or surface is characterized by a lackof corresponding radial dimensions, unlike regular surfaces such asplanes, cylinders and conic surfaces. Free-form surfaces are known tothe skilled person and widely used in engineering design disciplines.Typically non-uniform rational B-spline (NURBS) mathematics is used todescribe the surface forms; however, there are other methods such asGorden surfaces or Coons surfaces. The form of the free-form surfacesare characterized and defined not in terms of polynomial equations, butby their poles, degree, and number of patches (segments with splinecurves). Free-form surfaces can also be defined as triangulatedsurfaces, where triangles are used to approximate the 3D surfaces.Triangulated surfaces are used in Standard Triangulation Language (STL)files which are known to a person skilled in CAD design. The free-formstructures fit the surface of a body part, as a result of the presenceof a rigid basic structures therein, which provide the structures theirfree-form characteristics.

The term “rigid” when referring to the lattice structure and/orfree-form structures comprising them herein refers to a structureshowing a limited degree of flexibility, more particularly, the rigidityensures that the structure forms and retains a predefined shape in athree-dimensional space prior to, during and after use and that thisoverall shape is mechanically and/or physically resistant to pressureapplied thereto. In particular embodiments the structure is not foldableupon itself without substantially losing its mechanical integrity,either manually or mechanically. Despite the overall rigidity of theshape of the envisaged structures, the specific stiffness of thestructures may be determined by the structure and/or material of thelattice structure. Indeed, it is envisaged that the lattice structuresand/or free-form structures, while maintaining their overall shape in athree-dimensional space, may have some (local) flexibility for handling.As will be detailed herein, (local) variations can be ensued by thenature of the pattern of the lattice structure, the thickness of thelattice structure and the nature of the material. Moreover, as will bedetailed below, where the free-form structures envisaged herein compriseseparate parts (e.g. non-continuous lattice structures) which areinterconnected (e.g., by hinges or by areas of coating material), therigidity of the shape may be limited to each of the areas comprising alattice structure.

Generally, the methods envisaged herein are for dental appliancefabrication processes where the fabrication process includes designingan appliance worn on teeth to be covered by a free-form structure,manufacturing the mold, and providing the (one or more) latticestructures therein and providing the coating material in the mold so asto form the free-form structure. The free-form structures arepatient-specific, i.e. they are made to fit specifically on the anatomyor dentition of a certain patient, e.g., animal or human. FIG. 11Agenerally shows an overall exemplary method for fabricating a dentalappliance by capturing a 3D representation of a body part of a subject410. In this example, this may involve capturing the 3D representationof the surfaces, e.g. external contours, of a patient's dentition forcorrecting one or more malocclusions. For this purpose, the subject maybe scanned using a 3D scanner, e.g. a hand-held laser scanner, and thecollected data can then be used to construct a digital, threedimensional model of the body part of the subject. Alternatively, thepatient-specific images can be provided by a technician or medicalpractitioner by scanning the subject or part thereof. Such images canthen be used as or converted into a three-dimensional representation ofthe subject, or part thereof. Additional steps wherein the scanned imageis manipulated and for instance cleaned up may be envisaged.

With the captured 3D representation, a free-form structure comprisedgenerally of a lattice structure matching at least part of the surfaceof the body part, e.g., dentition, may be generated 412. Designing afree-form structure based on said three dimensional representation ofsaid body part, such that the structure is essentially complementary toat least part of said body part and comprises or consists of a latticestructure. In the lattice structure, one or more types and/or sizes ofunit cell may be selected, depending on the subject shape, the requiredstiffness of the free-form structure, etc. Different lattice structuresmay be designed within the free-form structure for fitting on differentlocations on the body part. The different lattice structures may beprovided with, e.g., a hinge or other movable mechanism, so that theycan be connected and/or, can be digitally blended together or connectedby beams in the basic structure to form a single part.

This step may also include steps required for designing the latticestructure, including for instances of defining surfaces on the positiveprint of the mask that may need different properties, different cellsizes and/or openings, generating the cells with the required geometryand patterning them as needed on the defined surfaces to cover saidsurfaces, and combining the separate cell patterns into a single solidpart. It should be noted that the requirements of the lattice structurewould be clear to a skilled person while designing the latticestructure. The skilled person will therefore use data obtained from hisown experience as well as data from numerical modeling systems, such asFE and/or CFD models.

The free-form lattice structure may then be actually manufactured, e.g.,by additive manufacturing methods 414. In certain embodiments, this mayinclude providing a coating material on the basic structure in whichcoating material is preferably a polymer.

These different steps need not be performed in the same location or bythe same actors. Indeed typically, the design of the free-formstructure, the manufacturing and the coating may be accomplished indifferent locations by different actors. Moreover, it is envisaged thatadditional steps may be performed between the steps recited above. Incoating or impregnating the free-form basic structure, the latticestructure may be impregnated with a certain material, such as a polymer,thereby generating the free-form structure. This may include steps suchas adding the polymeric material or other material into the dentalappliance, curing the material impregnating the lattice structure anddisassembling the dental appliance.

After manufacturing the free-form structure, the structure may gothrough a number of post-process steps including for instance cleaningup and finishing the free-form structure. Moreover, other applicationsof forming a rigid free-form structure as described herein may alsoinclude applications for, but not limited to, therapeutic, cosmetic andprotective applications.

In one particular application, the use of the free-form structuresdescribed herein may be used in the care and treatment of damaged skinsurfaces, such as burn wounds. In further embodiments, the use of thefree-from structures described herein may be used in the care,protection, and treatment of undamaged skin surfaces. According toadditional particular embodiments, the use of a free-form structure asdescribed herein may be used for cosmetic purposes. In furtherembodiments, the use of a free-form structure as described herein may beused for the delivery of treatment agents to the skin. In otherparticular embodiments, the structure further comprises one or moretherapeutic compositions which may be embedded in the coating material.In yet further embodiments, the use of the structures described hereinmay be used as prosthetic devices, e.g., for replacing a body part,where the free-forms structure may be made to be identical to themissing body part.

FIG. 11B shows another overall exemplary process for fabricating adental appliance having a lattice structure similarly to that shownabove in FIG. 11A. In this example, once the 3D representation has beencaptured 410, the amount of force required to move a tooth or teeth maybe determined and finite element analysis may be utilized to determinean appropriate thickness of aligner material needed for the associatedforce 410A to move a particular tooth or teeth. In this manner, one ormore oral appliances may be fabricated with varying material thicknessesin which regions which may not require much force are fabricated to havea relatively thinner region while regions of the appliance which mayrequire a greater amount of force to move the tooth or teeth may befabricated to have relatively thicker regions of material to create anoral appliance having directional strength (Differential Force)depending on the particular forces needed to correct particularmalocclusions. Simulations may be performed on the modeled dentition (oraligners) to confirm stress point handling for the various alignerthicknesses 410B.

Then as previously described, a free-form structure comprised generallyof a lattice structure matching at least part of the surface of the bodypart, e.g., dentition, may be generated 412 and the free-form latticestructure may then be actually manufactured, e.g., by additivemanufacturing methods 414. However, the one or more oral appliances maybe fabricated to have regions of relatively thickened and/or thinnedmaterial to accommodate the directional strength (Differential Force) ofthe oral appliances, as described in further detail below.

FIG. 12 shows a perspective view of an exemplary oral appliance 420having two parts 422 (for the upper dentition and lower dentition). Asshown, the oral appliance 420 generally includes a lattice structure 424which can be used in a process for manufacturing the final oralappliance. In the process, the lattice structure 424 may first be 3Dprinted in a shape which approximates the oral appliance to befabricated for correcting the malocclusion and the lattice structure maybe positioned within a dental appliance 426, 426′. Then, the dentalappliance 426, 426′ containing the formed lattice structure 424 may befilled with the impregnating material 428, e.g., polymer or othermaterials described herein. After setting of the impregnating material428, the dental appliance halves 426, 426′ are removed to yield thecoated oral appliance 420.

While the entire lattice structure 424 may be coated or impregnated bythe impregnating material 428, only portions of the lattice structure424 may be coated or particular surfaces of the lattice structure 424may be coated while leaving other portions exposed. Variations of theseembodiments are described in further detail below with respect to theoral appliance 420 shown in FIG. 12.

As can be appreciated, an approach to 3D printed progressive aligners ofvarying and/or increasing thickness has certain advantages. For example,the rate of incremental increase in thickness may not be dependent onstandard thicknesses of sheet plastic available as an industrialcommodity. An optimal thickness could be established for the 3D printingprocess. For example, rather than being limited to the, e.g., 0.040,0.060 and 0.080 in. thickness sequence, a practitioner such as anorthodontist could choose a sequence such as, e.g., 0.040, 0.053 and0.066 in. thickness, for an adult patient whose teeth are known toreposition more slowly compared to a rapidly growing adolescent patient.

Given the concept that an aligner formed from thinner material generatesgenerally lower corrective forces than an identically configured alignerformed from thicker material, it follows that an aligner could be 3Dprinted so as to be thicker in areas where higher forces are needed andthinner in areas where lighter forces are needed. Having the latitude toproduce aligners with first a default thickness and then areas ofvariable thickness could be favorably exploited to help practitionersaddress many difficult day-to-day challenges. For example, anymalocclusion will consist of teeth that are further from their desiredfinished positions than other teeth. Further, some teeth are smallerthan others and the size of the tooth corresponds to the absolute forcethreshold needed to initiate tooth movement. Other teeth may seem to bemore stubborn due to many factors including the proximity of the tooth'sroot to the boundaries between cortical and alveolar bony support. Stillother teeth are simply harder to correctively rotate, angulate, orup-right than others. Still other teeth and groups of teeth may need tobe bodily moved as rapidly as possible over comparatively large spans toclose open spaces. For at least such reasons, the option of tailoringaligner thickness and thus force levels around regions containing largerteeth or teeth that are further from their desired destinations, orthose stubborn teeth allows those selected teeth to receive higherforces than small, nearly ideally positioned teeth.

The free-form lattice structure for the dental appliances can be atleast partially fabricated by additive manufacturing (AM). Moreparticularly, at least the basic structure may be fabricated by additivemanufacturing using the lattice structure. Generally, AM can may includea group of techniques used to fabricate a tangible model of an objecttypically using 3D computer aided design (CAD) data of the object. Amultitude of AM techniques are available for use, e.g.,stereolithography, selective laser sintering, fused deposition modeling,foil-based techniques, etc. Selective laser sintering uses a high powerlaser or another focused heat source to sinter or weld small particlesof plastic, metal, or ceramic powders into a mass representing the 3Dobject to be formed. Fused deposition modeling and related techniquesmake use of a temporary transition from a solid material to a liquidstate, usually due to heating. The material is driven through anextrusion nozzle in a controlled way and deposited in the required placeas described among others in U.S. Pat. No. 5,141,680, which isincorporated herein by reference in its entirety and for any purpose.Foil-based techniques fix coats to one another by use of, e.g., gluingor photo polymerization or other techniques, and then cuts the objectfrom these coats or polymerize the object. Such a technique is describedin U.S. Pat. No. 5,192,539, which is incorporated herein by reference inits entirety and for any purpose.

Typically AM techniques start from a digital representation of the 3Dobject to be formed. Generally, the digital representation is slicedinto a series of cross-sectional layers which can be overlaid to formthe object as a whole. The AM apparatus uses this data for building theobject on a layer-by-layer basis. The cross-sectional data representingthe layer data of the 3D object may be generated using a computer systemand computer aided design and manufacturing (CAD/CAM) software.

The basic structure comprising the lattice structure may thus be made ofany material which is compatible with additive manufacturing and whichis able to provide a sufficient stiffness to the rigid shape of theregions comprising the lattice structure in the free-form structure orthe free-form structure as a whole. Suitable materials include, but arenot limited to, e.g., polyurethane, acrylonitrile butadiene styrene(ABS), polycarbonate (PC), PC-ABS, polyamide, polyamide with additivessuch as glass or metal particles, methylmethacrylate-acrylonitrile-butadiene-styrene copolymer, etc.

The lattice structure itself may be comprised of a rigid structure whichhas an open framework of, e.g., 3D printed lattices. Lattice structuresmay contain a plurality of lattices cells, e.g., dozens, thousands,hundreds of thousands, etc. lattice cells. Once the 3D model of thedentition is provided, the process may generate STL files to print thelattice version of the 3D model and create support structures wherenecessary. The system identifies where material is needed in anappliance and where it is not required, prior to placing and optimizingthe lattice.

The system may optimize dental lattices in two phases. First, it appliesa topology optimization allowing more porous materials with intermediatedensities to exist. Second, the porous zones are transformed intoexplicit lattice structures with varying material volume. In the secondphase, the dimensions of the lattice cells are optimized. The result isa structure with solid parts plus lattice zones with varying volumes ofmaterial. The system balances the relationship between material densityand part performance, for example, with respect to the stiffness tovolume ratio, that can impact design choices made early in the productdevelopment process. Porosity may be especially important as afunctional requirement for biomedical implants. Lattice zones could beimportant to the successful development of products where more than merestiffness is required. The system can consider buckling behavior,thermal performance, dynamic characteristics, and other aspects, all ofwhich can be optimized. The user may manipulate material density basedupon the result of an optimization process, comparing stronger versusweaker, or solid versus void versus lattice, designs. The designer firstdefines the objective, then performs optimization analysis to inform thedesign.

While 3D printing may be used, the lattices can also be made of strips,bars, girders, beams or the like, which are contacting, crossing oroverlapping in a regular pattern. The strips, bars, girders, beams orthe like may have a straight shape, but may also have a curved shape.The lattice is not necessarily made of longitudinal beams or the like,and may for example consist of interconnected spheres, pyramids, etc.among others.

The lattice structure is typically a framework which contains a regular,repeating pattern as shown in FIG. 12A, wherein the pattern can bedefined by a certain unit cell. A unit cell is the simplest repeat unitof the pattern. Thus, the lattice structure 424 is defined by aplurality of unit cells. The unit cell shape may depend on the requiredstiffness and can for example be triclinic, monoclinic, orthorhombic,tetragonal, rhombohedral, hexagonal or cubic. Typically, the unit cellsof the lattice structures have a volume ranging from, e.g., 1 to 8000mm³, or preferably from 8 to 3375 mm³, or more preferably from 64 to3375 mm³, or most preferably from 64 to 1728 mm³. The unit cell size maydetermine, along with other factors such as material choice and unitcell geometry, the rigidity (stiffness) and transparency of thefree-form structure. Larger unit cells generally decrease rigidity andincrease transparency, while smaller unit cells typically increaserigidity and decrease transparency. Local variations in the unit cellgeometry and/or unit cell size may occur, in order to provide regionswith a certain stiffness. Therefore, the lattice 424 may comprise one ormore repeated unit cells and one or more unique unit cells. In order toensure the stability of the lattice structure 424, the strips, bars,girders, beams or the like may have a thickness or diameter of, e.g.,0.1 mm or more. In particular embodiments, the strips, bars, girders,beams or the like may preferably have a thickness or diameter of, e.g.,0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 5 mm or more.The main function of the lattice structure 424 is to ensure a certainstiffness of the free-form structure. The lattice structure 424 mayfurther enhance or ensure transparency, as it is an open framework. Thelattice structure 424 can preferably be considered as a reticulatedstructure having the form and/or appearance of, e.g., a net or grid,although other embodiments may be used.

The stiffness of the lattice structure depends on factors such as thestructure density, which depends on the unit cell geometry, the unitcell dimensions and the dimensions of the strips, bars, girders, beams,etc. of the framework 432. Another factor is the distance, S, betweenthe strips and the like, or in other words, the dimensions of theopenings in the lattice structure, as shown in the detail exemplary viewof FIG. 12B. Indeed, the lattice structure is an open framework andtherefore comprises openings 434. In particular embodiments, the openingsize S of the lattice structure is between, e.g., 1 and 20 mm, between 2and 15 mm, or between 4 and 15 mm. In preferred embodiments, the openingsize is between, e.g., 4 and 12 mm. The size of the openings may be theequal to or smaller than the size of the unit cell 434 while in otherembodiments, the openings may be uniform in size or arbitrary in size.In yet another alternative, differing regions of the lattice may haveopenings which are uniform in size but which are different from otherregions.

In particular embodiments, the free-form structures may comprise alattice structure having one or more interconnected reticulated layers,as shown in the exemplary end view of FIG. 12C. For instance, thelattice structure may comprise one, two, three or more reticulatedlayers 438, where the structure comprises different at least partiallysuperimposed and/or interconnected layers 436, 436′, 436″ within thelattice structure. The degree of stiffness provided by the latticestructure may increase with the number of reticulated layers providedtherein. In further particular embodiments, the free-form structures maycomprise more than one lattice structure. The examples shown are merelyillustrative of the different embodiments.

For certain applications the lattice structure may further comprise oneor more holes with a larger size than the openings or unit cells asdescribed hereinabove. Additionally or alternatively, the latticestructure may not extend over the entire shape of the free-formstructure such that openings in the structure or regions for handling,e.g., tabs or ridges, and/or regions of unsupported coating material areformed. An example of such an application is a facial mask, where holesare provided at the location of the eyes, mouth and/or nose holes.Typically, these latter holes are also not filled by the coatingmaterial.

Similarly, in particular embodiments, the size of the openings which areimpregnated in and/or enclosed by the adjoining material may rangebetween, e.g., 1 and 20 mm. The holes in the lattice structure(corresponding to holes in the free-form structure) as described hereinwill also typically have a size which is larger than the unit cell.Accordingly, in particular embodiments, the unit cell size rangesbetween, e.g., 1 and 20 mm.

According to particular embodiments, as shown in the end view of FIG.12D, the envisaged free-form structure may contain regions 433 comprisedonly of the coating material 431. This may be of interest in areas whereextreme flexibility of the free-form structure is desired.

In particular embodiments, the envisaged free-form structure maycomprise a basic structure which contains, in addition to a latticestructure, one or more limited regions which do not contain a latticestructure, but are uniform surfaces, as shown in the detail perspectiveview of FIG. 12E. Typically these form extensions 435 from the latticestructure with a symmetrical shape (e.g. rectangular, semi-circle,etc.). Such regions, however, typically encompass less than, e.g., 50%,or more particularly less than, e.g., 30%, or most particularly lessthan, e.g., 20% of the complete basic structure. Typically they are usedas areas for handling (manual tabs) of the structure and/or forplacement of attachment structures (clips, elastic string, etc.). Inparticular embodiments, the basic structure may be comprised essentiallyof only a lattice structure.

It can be advantageous for the dental appliance structure to havecertain regions with a different stiffness (such as in the molar teethto provide added force). This can be achieved by providing a latticestructure with locally varying unit cell geometries, varying unit celldimensions and/or varying densities and/or varying thicknesses of thelattice structure (by increasing the number of reticulated layers), asshown in the exemplary detail perspective view of FIG. 12F. Accordingly,in particular embodiments, the lattice structure is provided withvarying unit cell geometries, varying unit cell dimensions, varyinglattice structure thicknesses and/or varying densities 437, 439.Additionally or alternatively, as described herein, the thickness of thecoating material may also be varied, as shown in FIG. 12G. Thus, inparticular embodiments, the free-form structure has a varying thicknesswith a region of first thickness 441 and a region of second thickness443. In further particular embodiments, the free-form structures mayhave regions with a different stiffness, while they retain the samevolume and external dimensions.

In particular embodiments of the free-form structures, the basicstructure or the lattice structure can be covered in part with a coatingmaterial which is different from the material used for manufacturing thelattice structure. In particular embodiments the lattice structure is atleast partly embedded within or enclosed by (and optionally impregnatedwith) the coating material, as shown in the exemplary detail end view ofFIG. 12H. In further embodiments, the coating material is provided ontoone or both surfaces of the lattice structure 436. In particularembodiments only certain surface regions of the basic structure and/orthe lattice structure in the free-form structure are provided with acoating material while portions may be exposed 445. In particularembodiments, at least one surface of the basic structure and/or latticestructure may be coated 431 for at least 50%, more particularly at least80%. In further embodiments, all regions of the basic structure having alattice structure are fully coated, on at least one side, with thecoating material. In further particular embodiments, the basic structureis completely embedded with the coating material, with the exceptions ofthe tabs provided for handling.

In further embodiments, the free-form structure comprises, in additionto a coated lattice structure, regions of coating material not supportedby a basic structure and/or a lattice structure.

Accordingly, in particular embodiments, the free-form structure maycomprise at least two materials with different texture or composition.In other embodiments, the free-form structure may comprise a compositestructure, e.g., a structure which is made up of at least two distinctcompositions and/or materials.

The coating material(s) may be a polymeric material, a ceramic materialand/or a metal. In particular embodiments, the coating material(s) is apolymeric material. Suitable polymers include, but are not limited to,silicones, a natural or synthetic rubber or latex, polyvinylchloride,polyethylene, polypropylene, polyurethanes, polystyrene, polyamides,polyesters, polyepoxides, aramides, polyethyleneterephthalate,polymethylmethacrylate, ethylene vinyl acetate or blends thereof. Inparticular embodiments, the polymeric material comprises silicone,polyurethane, polyepoxide, polyamides, or blends thereof.

In particular embodiments the free-form structures comprise more thanone coating material or combinations of different coating materials.

In specific embodiments, the coating material is a silicone. Siliconesare typically inert, which facilitates cleaning of the free-formstructure.

In particular embodiments, the coating material is an opticallytransparent polymeric material. The term “optically transparent” as usedherein means that a layer of this material with a thickness of 5 mm canbe seen through based upon unaided, visual inspection.

Preferably, such a layer has the property of transmitting at least 70%of the incident visible light (electromagnetic radiation with awavelength between 400 and 760 nm) without diffusing it. Thetransmission of visible light, and therefore the transparency, can bemeasured using a UV-Vis Spectrophotometer as known to the person skilledin the art. Transparent materials are especially useful when thefree-form structure is used for wound treatment (see further). Thepolymers may be derived from one type of monomer, oligomer or prepolymerand optionally other additives, or may be derived from a mixture ofmonomers, oligomers, prepolymers and optionally other additives. Theoptional additives may comprise a blowing agent and/or one or morecompounds capable of generating a blowing agent. Blowing agents aretypically used for the production of a foam.

Accordingly, in particular embodiments, the coating material(s) arepresent in the free-form structure in the form of a foam, preferably afoamed solid. Thus, in particular embodiments, the lattice structure iscoated with a foamed solid. Foamed materials have certain advantagesover solid materials: foamed materials have a lower density, requireless material, and have better insulating properties than solidmaterials. Foamed solids are also excellent impact energy absorbingmaterials and are therefore especially useful for the manufacture offree-form structures which are protective elements (see further). Thefoamed solid may comprise a polymeric material, a ceramic material or ametal. Preferably, the foamed solid comprises one or more polymericmaterials.

The foams may be open cell structured foams (also known as reticulatedfoams) or closed cell foams. Open cell structured foams contain poresthat are connected to each other and form an interconnected networkwhich is relatively soft. Closed cell foams do not have interconnectedpores and are generally denser and stronger than open cell structuredfoams. In particular embodiments, the foam is an “integral skin foam”,also known as “self-skin foam”, e.g., a type of foam with a high-densityskin and a low-density core.

Thus in particular embodiments, free-form structures may comprise abasic structure which includes a lattice structure which is at leastpartially coated by a polymeric or other material as described herein.For some applications, the thickness of the coating layer and theuniformity of the layer thickness of the coating are not essential.However, for certain applications, it can be useful to provide a layerof coating material with an adjusted layer thickness in one or morelocations of the free-form structure, for example, to increase theflexibility of the fit of the free-form structure on the body part.

The basic structure of the freeform structures envisaged herein can bemade as a single rigid free-form part which does not need a separateliner or other elements. Independent thereof it is envisaged that thefree-form structures can be further provided with additional components447 such as sensors, straps, or other features for maintaining thestructure in position on the body, or any other feature that may be ofinterest in the context of the use of the structures and integratedwithin or along the structure, as shown in FIG. 12I. Various examples ofsensors which may be integrated are described in further detail herein.

In certain embodiments, the free-form structure comprises a single rigidlattice structure (optionally comprising different interconnected layersof reticulated material). However, such structures often only allow alimited flexibility, which may cause discomfort to a person or animalwearing the free-form structure. An increase in flexibility can beobtained if the free-form structure comprises two or more separate rigidlattice structures which can move relative to each other. These two ormore lattice structures are then enclosed by a material as describedabove, such that the resulting free-form structure still is made orprovided as a single part. The rigidity of the shape of the free-formstructure is ensured locally by each of the lattice structures, whileadditional flexibility during placement is ensured by the fact thatthere is a (limited) movement of the lattice structures relative to eachother. Indeed, in these embodiments, the coating material and/or a morelimited lattice structure) will typically ensure that the latticestructures remain attached to each other.

In particular embodiments, the lattice structures are partially orcompletely overlapping. However, in particular embodiments, thedifferent lattice structures are non-overlapping. In further particularembodiments, the lattice structures are movably connected to each other,for example via a hinge or other movable mechanism 449, 449′, as shownin the detail end view of FIG. 12J. In particular embodiments theconnection is ensured by lattice material. In further particularembodiments the lattice structures may be interconnected by one or morebeams which form extensions of the lattice structures. In furtherembodiments the lattice structures are held together in the free-formstructure by the coating material. An example of such a free-formstructure is a facial mask with a jaw structure that is movable withrespect to the rest of the mask. Accordingly, in particular embodiments,the lattice structure comprises at least two separate lattice structuresmovably connected to each other, whereby the lattice structures areintegrated into the free-form structure, as shown.

The free-form structure may be used for wound treatment as describedherein. For optimal healing, the free-form structure provides a uniformcontact and/or pressure on the wound site or specific locations of thewound site. The lattice structure makes it simple to incorporatepressure sensors into the free-form structure according to the presentinvention. The sensors can be external sensors, but may also be internalsensors. Indeed, the lattice structure can be designed such that itallows mounting various sensors at precise locations, as describedabove, before impregnating and/or enclosing the lattice structure by apolymer or other material.

Additionally or alternatively, the free-form structure may comprise oneor more other sensors, as described above in FIG. 12I, such as atemperature sensor, a moisture sensor, an optical sensor, a straingauge, an accelerometer, a gyroscope, a GPS sensor, a step counter, etc.Accelerometers, gyroscopes, GPS sensors and/or step counter may forexample be used as an activity monitor. Temperature sensor(s), moisturesensor(s), strain gauge(s) and/or optical sensor(s) may be used tomonitor the healing process during wound treatment. Specifically, theoptical sensor(s) may be used to determine collagen fiber structure asexplained in US Pat. App. 2011/0015591, which is hereby incorporated byreference in its entirety and for any purpose.

Accordingly, in particular embodiments the free-form structure furthercomprises one or more external and/or internal sensors. In specificembodiments, the free-form structure comprises one or more internalsensors. In certain embodiments, the free-form structure comprises oneor more pressure and/or temperature sensors.

The skilled person will understand that in addition to the sensor(s),also associated power sources and/or means for transmitting signals fromthe sensor(s) to a receiving device may be incorporated into thefree-form structure, such as wiring, radio transmitters, infraredtransmitters, and the like.

In particular embodiments, at least one sensor may comprisemicro-electronic mechanical systems (MEMS) technology, e.g., technologywhich integrates mechanical systems and micro-electronics. Sensors basedon MEMS technology are also referred to as MEMS-sensors and such sensorsare small and light, and consume relatively little power. Non-limitingexamples of suitable MEMS-sensors are the STTS751 temperature sensor andthe LIS302DL accelerometer STMicroelectronics.

As shown in FIG. 12K, the lattice structure also allows providing thefree-form structure with one or more (internal) channels 451. Thesechannels may be used for the delivery of treatment agents to theunderlying skin, tissue, or teeth. The channels may also be used for thecirculation of fluids, such as heating or cooling fluids.

One philosophy of orthodontic treatment is known as “Differential Force”called out for the corrective forces directed to teeth to be closelytailored according to the ideal force level requirements of each tooth.The Differential Force approach was supported by hardware based oncalibrated springs intended to provide only those ideal force levelsrequired. Carrying the concepts of the Differential Force approachforward to the precepts of aligner fabrication, one can appreciate thatCNC-machined aligners exhibiting carefully controlled variable thicknesscan accomplish the Differential Force objectives on a tooth-by-toothbasis. The compartments surrounding teeth can have wall thicknessesestablished at the CAD/CAM level by a technician based on the needs ofeach tooth. A 3D printed aligner can have a limitless series of regions,each with a unique offset thickness between its inner and outersurfaces.

Prior to installing such devices, a practitioner may assess the progressof a case at mid-treatment for example and in particular, make note ofproblem areas where the desired tooth response is lagging or instanceswhere particular teeth are stubbornly not moving in response totreatment forces. The 3D printed structure can include a group of smalldevices that are intended to be strategically positioned and 3D printedwith an aligner's structure. Such devices are termed “alignerauxiliaries.” FIG. 13 is a detail view of a portion of an aligner 440showing a 3D printed area 442 that is machined allowing thicker materialto accept an elastic 444. Other 3D printed geometries of interest wouldbe divots or pressure points, creating openings/windows on the alignerfor a combination treatment, e.g., forming hooks on the aligner forelastic bands, among others. Aligner auxiliaries may be installed inthose locations to amplify and focus corrective forces of the aligner toenhance correction. For example, an auxiliary known as a tack can beinstalled after a hole of a predetermined diameter is pierced through awall of a tooth-containing compartment of an aligner. The diameter ofthe hole may be slightly less than the diameter of a shank portion ofthe tack which may be printed directly on the aligner. Suchprogressively-sized tacks and other auxiliary devices are commerciallyavailable to orthodontists who use them to augment and extend the toothposition correcting forces of aligners.

Bumps can also be used and serve to focus energy stored locally in theregion of the aligner's structure adjacent to a bump. Theinward-projecting bump causes an outward flexing of the aligner materialin a region away from the tooth surface. Configured in this way, bumpsgather stored energy from a wider area and impinge that energy onto thetooth at the most mechanically advantageous point, thus focusingcorrective forces most efficiently. An elastic hook feature 450 can be3D printed directly in an otherwise featureless area of an aligner'sstructure, as shown in the side views of FIGS. 14A and 14B. Elastichooks may also be used as anchor points for orthodontic elastics thatprovide tractive forces between sectioned portions of an aligner (or analigner and other structures fixedly attached to the teeth) as neededduring treatment.

Aside from hook features 450, other features such as suction features452 may be fabricated for adherence to one or more particular teeth T,as shown in the partial cross-sectional view of FIG. 14C. In thismanner, the aligner may exert a directed force 454 concentrated on theone or more particular teeth.

In yet another embodiment, as shown in the perspective view of FIG. 14D,the occlusal surfaces of the aligner may be fabricated to have areasdefined to facilitate eating or talking by the patient. Such featuresmay include occlusal regions which are thinned, made into flattenedsurfaces 456, or made with any number of projections 458 to facilitateeating.

Additionally, different portions of the aligners may be fabricated tohave different areas 460 of varying friction, as shown in theperspective view of FIG. 14E. Such varying areas may be formed, e.g.,along the edges to prevent tearing of the aligner material.

Additional attachments can be formed on the 3D printed dental appliancessuch as particulate coatings. The particulate coating 462 may be formedon the tooth engaging surface of the lattice 3D printed appliance in anyconvenient manner, e.g., fusion, sintering, etc., as shown in theperspective view of FIG. 14F. The particles making up the coating may beany convenient shape, including a spherical shape or an irregular shape,and may be constructed of metal (including alloys), ceramic, polymer, ora mixture of materials. The particulate coating adhered to the toothengaging surface may take the form of discrete particles which arespaced apart from each other on the surface, or the form of a layer ormultiple layers of particles bonded together to produce a network ofinterconnected pores. The particulate coating provides a porousinterface into which a fluid bonding resin may readily flow andpenetrate. Upon curing of the resin to solid form, mechanical interlockis achieved between the cured resin and the particulate coating. Undersome circumstances chemical bonding in addition to this mechanicalbonding may be achieved, e.g., by the use of polycarboxylate or glassionomer cements with stainless steel and other metallic substrates andwith ceramic substrates.

For a coating of integrally-joined particles which make up a porousstructure having a plurality of interconnected pores extendingtherethrough, the particles are usually about −100 mesh and preferably amixture of particles of varying particle sizes restricted to one ofthree size ranges, e.g., −100+325 mesh (about 50 to about 200 microns),−325+500 mesh (about 20 to about 50 microns), and −500 mesh (less thanabout 20 microns). The size of the particles in the porous structuredetermines the pore size of the pores between the particles.Smaller-sized pores are preferred for fluid resin bonding agents whereaslarger-sized pores are preferred for more viscous cementitious bondingmaterials. The selection of particle size is also used to control theporosity of the coating to within the range of about 10 to about 50% byvolume.

An adequate structural strength is required for the composite ofsubstrate and coating, so that any fracture of the joint of the bracketto the tooth occurs in the resin and not in the coating. To achieve thiscondition, the structural strength of the coating, the interface betweenthe coating and the substrate and the substrate itself is at least 8MPa.

FIGS. 15A to 15D show exploded views of alternative lattice structureswhich may be utilized in any of the embodiments described herein. Thelattice structures have open faces and are layered and can also beregarded as two or more interconnected reticulated layers or asstructures comprising only one layer or more than two layers.

FIG. 15A shows a first and second perspective view of the latticestructure 470 having a triangular cell pattern and an example of thestructure 470 reconfigured into an alternative or compressedconfiguration 470′. FIG. 15B shows a first and second perspective viewof the lattice structure 472 having a polygonal cell pattern and anexample of the structure 472 reconfigured into an alternative orcompressed configuration 472′. FIG. 15C shows a first and secondperspective view of the lattice structure 474 having a diamond cellpattern and an example of the structure 474 reconfigured into analternative or compressed configuration 474′. FIG. 15D shows aperspective view of the lattice structure 476 having a linked diamondcell pattern.

During the 3D printing process, the formed oral appliance may need to besupported by an intermediate structure given the complex shapes beingconstructed. Such intermediate structures may be used temporarily andthen removed, separated, or otherwise disengaged from the oral appliancebeing formed.

FIG. 16 shows a cross-sectional side view of an exemplary 3D printeddental appliance 510 with a temporary support structure 514 positionedwithin the appliance 510.

Typically, the dental appliance 510 is designed to stay in a patient'smouth more than 518 hours a day for about one month. Aside fromdurability, the shell of the dental appliance 510 is desirably thintypically having a thickness of about 0.5 mm. To be able to 3D printsuch a shell or dental portion for covering the teeth or tooth, thestructure of FIG. 16 may utilize the inner support structure 514 tostructurally support or buttress the appliance 510 formed upon thesupport structure 514. Because the occlusal surface 512 of the oralappliance 510 may have a complex anatomy (or terrain), the interfacingsurface 516 of the support structure 514 may be formed to mirror theocclusal surface 512 so that the occlusal surface 512 formed upon theinterfacing surface 516 during the manufacturing process sufficientlysupports the oral appliance 510.

Once formation of the appliance 510 has been completed, the supportstructure 514 may be readily removed from the opening 518 defined by theappliance 510. Hence, in one embodiment, the width of the supportstructure 514 may be similar to the opening 518 of the appliance 510 toallow for removal of the support 514 from the appliance 510. Theappliance 510 may be fabricated from a number of different types ofpolymers, e.g., silicone, polyurethane, polyepoxide, polyamides, orblends thereof, etc., and the support structure 514 may be fabricatedfrom the same, similar, or different material than the appliance 510.Fabricating the support structure 514 from a material different than thematerial of the appliance 510 may facilitate the separation and removalof the support structure 514 from the appliance 510 when finished.

Aside from having the support structure 514 positioned directly belowthe appliance 510 during fabrication, other embodiments may include asupport structure formed as one or more layers, as shown in the partialcross-sectional side views of FIGS. 17A and 17B. FIG. 17A shows oneembodiment of an oral appliance 520 during fabrication where an innercore layer 522 may be formed (e.g., via 3D printing) of a first materialconfigured and shaped to follow the contours of the dentition. With theinner core layer 522 fabricated, an inner appliance layer 524 may beprinted upon an interior surface of the inner core layer 522 and anouter appliance layer 526 may be printed upon an exterior surface of theinner core layer 522. The inner core layer 522 may thus be formed to beslightly oversized relative to the dentition to allow for thefabrication of the inner appliance layer 524 to size. The innerappliance layer 524 and outer appliance layer 526 may be printed uponthe inner core layer 522 either sequentially or simultaneously to formthe desired oral appliance 520. Subsequently, the inner core layer 522may be melted, washed, or otherwise dissolved, e.g., via chemicals,leaving the completed oral appliance 520 with inner appliance layer 524and outer appliance layer 526 intact.

In another embodiment, FIG. 17B shows a cross-sectional side view of anarrangement where the oral appliance 528 may be fabricated by anappliance layer 530 formed between an inner core layer 532 and outercore layer 534. The inner core layer 532 may be formed to be slightlyundersized relative to the dentition to allow for the fabrication of theappliance layer 530 to size. Once the appliance layer 530 has beenfabricated while supported by the inner core layer 532 and outer corelayer 534, both the inner core layer 532 and outer core layer 534 may beremoved or otherwise dissolved leaving the appliance layer 530.

In yet another embodiment, the oral appliance may be fabricated withvarious features such as projections, protrusions, or other shapes forproviding additional flexibility in treating the patient. FIG. 18 showsa cross-sectional side view of one example of a printed oral appliance540 having a pocket or cavity 542 formed along a side portion of thedevice, e.g., for receiving an attachment such as an elastic that can beplaced upon the pocket or cavity 542. In this example, the supportstructure can include a feature or projection 544 which causes thecorresponding pocket or cavity 542 to protrude from the oral appliance540, as shown. Certain features can be 3D printed for future assembly toprovide additional treatment options and improve the effectiveness ofthe oral appliance. In other embodiments, the support structure may beformed without any additional features but the feature or projection 544may be adhered or otherwise secured to selected regions of the supportstructure for selectively forming the corresponding pocket or cavity 542upon the oral appliance 540. The feature or projection may be optionallydesigned, e.g., to enable non-isotropic friction in one direction whichhelps device to grab teeth better and move to its designed position.

In yet another embodiment, features or projections may instead beincorporated into the oral appliance to impart additional forces or tofacilitate tooth movements. One example is shown in the top view of FIG.19 which illustrates a projection 550 (e.g., a polymeric or metallicball) positioned by an oral appliance (not shown for clarity purposes)between two adjacent teeth 554, 556. The projection 550 may befabricated as part of the oral appliance which extends from theappliance and into contact against specified regions of a tooth orteeth, e.g., to facilitate a separation movement between the adjacentteeth 554, 556. While a single projection 550 is shown, such aprojection or multiple projections may be used within the oralappliance.

Aside from projections, the oral appliance 560 may also define a numberof channels, grooves, or features which support the use of additionaldevices. An exemplary oral appliance 560 is shown in the top view ofFIG. 20 positioned upon the teeth 562 of a subject and further havingslots 564, 566 defined within the oral appliance 560 for supportingwires 568 within. The oral appliance 560 may be configured and printedwith the slots 564, 566 to receive, e.g., wires, hooks, rubber bands,etc., for supplementing the corrective forces imparted by the oralappliance 560 for correcting malocclusions as well as to enhance thematerial strength and prevent material relaxation, e.g., in cases ofarch expansion. The wire 568 is show anchored within the slots 564, 566of oral appliance 560 for illustrative purposes but alternativevariations for slot positioning or incorporating other features orelements may also be used.

In another embodiment, due to accurate gingival modeling, the shell ofthe oral appliance can be extended or thickened to cover the gum areaswithout hurting patients. Such extended areas can strengthen the shell,e.g., plastic, especially at times when a shortened plastic shell maynot be able to provide the strength needed.

FIG. 21 shows an exemplary process for adjusting the thickness of the 3Dprinted oral appliance. With the subject's dentition scanned andelectronically converted, the upper and lower arch models 570 may beloaded into the memory of a computer system having a programmableprocessor. The bite registration may be set and the resulting digitalmodel may be mounted on a virtual articulator 572. The system may beprogrammed to generate an initial shell model having a predeterminedthickness 574 where the thicker the portions of the oral applianceprovides a relatively stronger region. The practitioner can incorporatefeatures such as the projections 550 shown above in FIG. 19 and/orfurther incorporate additional features such as slots 564, 566 or anyother features into the model of the oral appliance. The system may beprogrammed to then activate an articulator to perform a simulated bite576 between the upper and lower arch models to calculate any overlapbetween the upper and lower arch shell 578. Any resulting stresses onthe shell model of the oral appliance may also be determined.

The system may then remove any overlap by trimming off the shellmaterial 580 in the model and any isolated islands or peninsular piecesmay then be removed as well 582. The resulting 3D model may then beexported to a 3D printer 584 for fabricating the dental appliance orshell.

FIG. 22 shows another exemplary process for determining the thickness ofan oral appliance based on physical simulations. In this process, thedigital model of the lower arch and upper arch may be loaded 590 intothe memory of a computer system, as above. The new desired configurationfor the arch and/or dentition may be input into the system which maycalculate the necessary movements to occur for the tooth or teeth 592.The system may then generate an analytical model for an initial shellshape 594. The system may further run an analytical model to optimizeshell shapes, including thicknesses and potential ancillary componentsor parts which may be needed or desired 596. The analytical 3D model maybe further optimized for best patient comfort and resin costminimization 598 and the result may then be provided to a 3D printer 600for fabricating the oral appliance or shell.

Generally, the pressure formed plastic shell forming conventional oralappliances have intrinsic short-comings. Ideally the plastic shell has arelatively thinner layer (e.g., thinner than other regions of theappliance) on regions of the appliance which contact the occlusal areasof the patient's dentition so the patient's bite is unaffected when inuse during treatment. On the other hand, the embrasure or side surfaceareas are ideally relatively thicker to provide enough force to push thetooth or teeth to its designated location for correcting malocclusions.Oftentimes, these embrasure regions are stretched thinner during theforming process for the oral appliance. In forming the oral appliance,the system described herein may determine the areas of the oralappliance which affects the patient's bite and may configure theappliance to be thinner in particular areas or may even remove somematerial from the appliance entirely to form a hole.

Free-form lattice structures which fit at least part of the surface,e.g. external contour, of a body part may be used to form the oralappliance. Specifically, the embodiments described may utilize free-formlattice structures for forming or fabricating appliances which aredesigned for placement or positioning upon the external surfaces of apatient's dentition for correcting one or more malocclusions. Thefree-form structure is at least partially fabricated by additivemanufacturing techniques and utilizes a basic structure comprised of alattice structure. The lattice structure may ensure and/or contribute toa free-form structure having a defined rigidity and the latticestructure may also ensure optimal coverage on the dentition by a coatingmaterial which may be provided on the lattice structure. The latticestructure is at least partly covered by, impregnated in, and/or enclosedby the coating material. Furthermore, embodiments of the latticestructure can contribute to the transparency of the structure.

The term “free-form lattice structure”, as used herein, refers to astructure having an irregular and/or asymmetrical flowing shape orcontour, more particularly fitting at least part of the contour of oneor more body parts. Thus, in particular embodiments, the free-formstructure may be a free-form surface. A free-form surface refers to an(essentially) two-dimensional shape contained in a three-dimensionalgeometric space. Indeed, as detailed herein, such a surface can beconsidered as essentially two-dimensional in that it has limitedthickness, but may nevertheless to some degree have a varying thickness.As it comprises a lattice structure rigidly set to mimic a certain shapeit forms a three-dimensional structure.

Typically, the free-form structure or surface is characterized by a lackof corresponding radial dimensions, unlike regular surfaces such asplanes, cylinders and conic surfaces. Free-form surfaces are known tothe skilled person and widely used in engineering design disciplines.Typically non-uniform rational B-spline (NURBS) mathematics is used todescribe the surface forms; however, there are other methods such asGorden surfaces or Coons surfaces. The form of the free-form surfacesare characterized and defined not in terms of polynomial equations, butby their poles, degree, and number of patches (segments with splinecurves). Free-form surfaces can also be defined as triangulatedsurfaces, where triangles are used to approximate the 3D surfaces.Triangulated surfaces are used in Standard Triangulation Language (STL)files which are known to a person skilled in CAD design. The free-formstructures fit the surface of a body part, as a result of the presenceof a rigid basic structures therein, which provide the structures theirfree-form characteristics.

The term “rigid” when referring to the lattice structure and/orfree-form structures comprising them herein refers to a structureshowing a limited degree of flexibility, more particularly, the rigidityensures that the structure forms and retains a predefined shape in athree-dimensional space prior to, during and after use and that thisoverall shape is mechanically and/or physically resistant to pressureapplied thereto. In particular embodiments the structure is not foldableupon itself without substantially losing its mechanical integrity,either manually or mechanically. Despite the overall rigidity of theshape of the envisaged structures, the specific stiffness of thestructures may be determined by the structure and/or material of thelattice structure. Indeed, it is envisaged that the lattice structuresand/or free-form structures, while maintaining their overall shape in athree-dimensional space, may have some (local) flexibility for handling.As will be detailed herein, (local) variations can be ensued by thenature of the pattern of the lattice structure, the thickness of thelattice structure and the nature of the material. Moreover, where thefree-form structures envisaged herein comprise separate parts (e.g.non-continuous lattice structures) which are interconnected (e.g., byhinges or by areas of coating material), the rigidity of the shape maybe limited to each of the areas comprising a lattice structure.

Descriptions of dental appliance fabrication processes may be found infurther detail in U.S. Prov. App. 62/238,514 filed October 7, 2015,which is incorporated herein by reference in its entirety and for anypurpose.

Generally, the fabrication process includes designing an appliance wornon teeth to be covered by a free-form structure, manufacturing the mold,and providing the (one or more) lattice structures therein and providingthe coating material in the mold so as to form the free-form structure.The free-form structures are patient-specific, i.e. they are made to fitspecifically on the anatomy or dentition of a certain patient, e.g.,animal or human. In fabricating the oral appliance, the 3Drepresentation of the surfaces, e.g. external contours, of a patient'sdentition for correcting one or more malocclusions may be captured via a3D scanner, e.g. a hand-held laser scanner, and the collected data canthen be used to construct a digital, three dimensional model of the bodypart of the subject. Alternatively, the patient-specific images can beprovided by a technician or medical practitioner by scanning the subjector part thereof. Such images can then be used as or converted into athree-dimensional representation of the subject, or part thereof.Additional steps wherein the scanned image is manipulated and forinstance cleaned up may be envisaged.

In fabricating oral or dental appliances which are used to treatmalocclusions in a patient's dentition, the oral appliance may beinitially formed via, e.g., thermal forming or three-dimensional (3D)printing techniques. Once formed, the oral appliance may require furtherprocessing to trim excess material for ensuring a good fit on thepatient. However, trimming this excess is typically a time-consumingprocess which requires a separate step after forming the appliance.

In one embodiment, the forming and cutting of the oral appliance may beaccomplished in an automated process and with a single machine.Generally, a patient's scanned dentition may be used to create one ormore molds of the dentition where each subsequent mold is configured tosubsequently follow a corrective path for one or more teeth forcorrecting malocclusions in the dentition. Each of the one or more moldsmay be used as a mold for thermal forming or 3D printing a correspondingoral appliance upon the molds. The resulting oral appliances may be usedin sequence to move the dentition for correcting the malocclusions.

FIG. 23 shows an exemplary process for utilizing computerized orcomputer numerical control (CNC) for fabricating the oral appliances.Typical CNC systems and end-to-end component design is highly automatedusing computer-aided design (CAD) and computer-aided manufacturing (CAM)dental software. The process begins by loading digital models of thelower and upper arches 710 of the subject's dentition into a computersystem having a processor. This may involve capturing the 3Drepresentation of the surfaces, e.g. external contours, of a patient'sdentition for correcting one or more malocclusions. For this purpose,the subject may be scanned using a 3D scanner, e.g. a hand-held laserscanner, and the collected data can then be used to construct a digital,three dimensional model of the body part of the subject. Alternatively,the patient-specific images can be provided by a technician or medicalpractitioner by scanning the subject or part thereof. Such images canthen be used as or converted into a three-dimensional representation ofthe subject, or part thereof.

With the digital model of the subject's dentition loaded into thecomputer system, the process then calculates a rule-based cutting looppath 712 on the digital model for determining a path along which the CNCmachine may follow for trimming the mold upon which the oral applianceis fabricated. Once the cutting loop path has been determined, theprocess may then reduce the model complexity by applying a drape wall714 (as described in further detail below) which digitally extends fromthe cutting loop path towards a bottom of the mold model (e.g., awayfrom the portion of the appliance which contacts the teeth and towardsthe portion of the appliance which extends towards the gums). The drapewall functions by defining a region of the oral appliance which can beignored since this portion is to be removed or trimmed.

The digital model may then be rotated around its center in relation to areference plane in order to calculate a cutting blade tilt angle andblade height 716 (relative to the reference plane) which may be appliedduring the actual trimming procedure. With this information, the code tobe sent to the CNC machine may be generated based on the stageconfiguration to be utilized 718. A physical mold base to be used in theprocessing procedure may be trimmed and one or more anchoring featuresmay be incorporated into the mold base for securing a holding jig whichmay be used to secure the oral appliance 720 to the mold base. Thecompleted digital model may then be exported as, e.g., a 3D printeracceptable model 722, for printing the oral appliance or mold upon whichan oral appliance may be formed.

FIGS. 24 and 25 show side views of a portion of a digital model of apatient's dentition showing a tooth 730 and gums 732, as an example. Incalculating a rule-based cutting loop path 712, as shown in FIG. 23above, the scanned image of the patient's dentition may be processed toidentify the interface areas between the teeth and gums 732. One or moremarkers 734, 736 may be digitally placed on the model at these interfaceregions such that the markers 734, 736 are opposed to one another on themodel. A boundary or trim line 742 may then be defined to extend betweenthe markers 734, 736 such that the trim line 742 follows the borderbetween the teeth and gums. With the trim line 742 identified on themodel, a series of drop lines 738, 740 which are parallel to one anotherand spaced apart, e.g., uniformly, relative to one another may be formedto begin from the trim line 742 and extend away from the trim line 742and away from the dentition in a straight path. This base region 744formed by the drop lines 738, 740 below the trim line 742, i.e., awayfrom or opposite to the dentition, may be identified and demarcated as aregion to be removed from the mold.

To ensure that the height of the mold including the base region 744 doesnot excessively stretch the material forming the oral appliance, thesystem may be used to determine the lowest point (relative to the trimline 742 and appliance 730) for trimming the entire mold just above thisidentified lowest point. In one embodiment, the trimming may be donewith a predetermined margin, e.g., 2 mm, above the lowest identifiedpoint. The base region wall can also be tapered slightly based on theheight of the base region wall so that the width of the base region 744tapers from a larger width adjacent to the trim line 742 down to arelatively smaller width away from the trim line 742. The resulting moldformed from the dentition (or corrected dentition) is shown in the sideview of FIG. 25 where the base region 744 has a minimum height of thepredetermined margin, e.g., 2 mm.

Once the mold has been formed with the base region 744, the mold may befurther processed. A bottom view of a formed mold 750 is shown in FIG.26 with slots 752, 754 formed into a surface 756 of the mold 750 intowhich tools or anchors can be inserted for securing the mold 750 inplace during further processing procedures. FIG. 27, for example, showsa side view of the fabricated mold 750 secured along its interfacesurface 756 and anchored via slots 752, 754 to a surface 762 of aplatform 760. FIG. 28 shows one configuration where the platform 760holding the physical mold 750 for pressure-forming the oral aligner maybe positioned upside down, i.e., such that the mold 750 is held in aninverted position as shown. The platform 760 may be fixed or securedupon a stage 768 which may be actuated to move the platform 760 and mold750 in a vertical direction 764 (up/down) or linearly 766 within a planedefined by the stage 768 and platform 760, as shown in FIG. 28, tofacilitate cutting or trimming processes for the mold 750. The stage 768may also be actuated to rotate 770 the platform 760 and mold 750 withinthe plane defined by the stage 768 such that the stage 768 rotates aboutan axis which may be aligned to be collinear with a central axis 772 ofthe mold 750, as shown in FIG. 29.

Another configuration may position the stage 768 relative to a bladewhich may be translated and/or rotated relative to mold 750 and stage768. The system may calculate each motion stage parameters and while themold 750 is moved rotationally, the blade may be used to cut or trim themold 750, as needed. This may involve rotating the model 750 around itscenter and calculating the blade tilt angle and blade height 716, asdescribed above.

Yet another configuration may involve moving the stage 768 and mold 750relative to a stationary blade such that the mold 750 is rotated,tilted, and/or translated by the stage 768 while the position of theblade remains unchanged. The system then adjusts different tools to trimthe mold 750 at the pre-designated cutting path. In this or any othervariation, the blade can include a mechanical blade or a laser cuttingtool and software may be used to calculate the laser focus to easiermove the source back and force or attenuate its power to focus and cutthe mold 750 at designated locations.

In one implementation for processing the mold, FIG. 30 shows a top viewof a mold 750 positioned upon a stage and rotated relative to astationary cutting blade 780. The mold 750 may be secured to theunderlying platform and stage and rotated within the plane of theplatform in the direction 770 about its central axis 772 which may becoincident with the axis of rotation defined by the stage. The cuttingblade 780 having a cutting edge 782 may be positioned relative to themold at the predetermined height and angle relative to the mold 750, asdescribed herein, to trim the mold 750 as it rotates.

In this variation, instead of generating a complex 3D cutting curve, thesystem simply uses a 2D flat curve by optionally setting a water markcutting plane. The advantage is that no numerical controller is neededto cut the molds. Instead, the mold 750 can be simply placed by hand androtated (e.g., manually or automatically), as shown, to push it throughor past the cutting blade 780. The action may be similar to cutting awood board with a circular motion rather than a straight or linearmotion.

Another advantage of this configuration is the ability to utilize aseparate fixture which can be used to sandwich the material forming theoral appliance after placement upon the mold, e.g., when thermal formingthe oral appliance. The material from which the oral appliance isthermal formed, if used for fabrication, may be secured directlyremoving the need for yet another fixture on the mold itself. Oneimplementation uses a two-dimensional (2D) laser cutting tool that canbe used to cut along a flat curve formed by a horizontal silhouette linegenerated by a projection to the base surface.

FIG. 31 shows a side view of one embodiment where the mold 750 ispositioned above a platform 760 with the plastic shell mold 792 afterthermal forming upon the mold 750. The entire assembly of the mold 750,platform 760, and shell mold 792 rests on a flat bottom fixture base 790having a clamping fixture with one or more clamping plates 794, 796 oneither side to secure the mold 750 and shell mold 792. The fixtureassembly may be used to secure the shell mold 792 for further processingsuch as trimming. Once the processing has been completed, the clampingplates 794, 796 may be released and the shell mold 792 and/or mold 750may be removed from the fixture base 790.

In the event that the physical mold is processed by laser cutting, thesteps shown in the flow diagram of FIG. 32 may be implemented in anotherembodiment. Initially, a digital model of the lower and upper arches maybe loaded in the system 800, as described previously. The system maythen calculate a rule based cutting loop path for the 2D cutting system802, as discussed above. Model complexity may be reduced by applying thedrape wall from the cutting loop 804, as also discussed above. Theprocess trims the mold base above a water mark 806 which may beimprinted upon the mold to demarcate a boundary. For laser cutters, thesystem may generate a 2D laser cutting path using vertical projects 808and determine the border of the shadow as the cutting path 810. Thesystem may then export the 3D printer model 812 for fabrication. Theprocess may be repeated for each subsequent mold used for fabricatingone or more of the corresponding oral appliances.

Regardless of how the mold is trimmed or how the oral appliance isprocessed upon the mold, the separation and release of the shell(aligner or oral appliance) from the mold can be generally difficult dueto the lack of any features for grabbing the mold. To address this, oneor more holes or cavities 822 may be drilled or otherwise defined atvarious locations within the mold 820 and optionally at an angle 826relative to a normal direction of the mold, as shown in the end view ofFIG. 33. The angling of the hole or cavity 822 enables the insertion ofa tool 824 which may be positioned within to provide a counterforce forreleasing and removing an oral appliance 828 formed upon the mold 820.

Another embodiment shown in the end view of FIG. 34 which illustrates anend view of a mold 830 formed to have a hole or cavity 832 which extendsthrough the bottom of the mold 830 and into proximity of the top of themold, i.e., where the model of the patient's dentition is located. Athin layer 834 of the mold may extend over the hole 832 to provide asurface upon which the oral appliance 828 may be fabricated, asdescribed herein. However, once fabrication of the oral appliance 828has been completed and trimmed suitably, the tip 838 of a tool 836appropriately sized may be inserted into the opening 832 and pushedthrough the thin layer 834 of the mold 830 and into contact against aninner surface of the oral appliance such that the oral appliance 828 maybe urged to release from the mold 830. Alternatively, the tool 836 maycomprise an air blower so that the tip 838 may be positioned within theopening 832 into proximity of the layer 834, as shown by the detail viewD, where a jet of air introduced through tip 838 may be break throughthe layer 834 and urge the oral appliance 828 to release from the mold830.

To ensure that the mold 830 retains its strength during fabrication ofthe mold, oral appliance, or release of the oral appliance from themold, the mold 830 may be optionally fabricated to include a honeycomb,mesh, or other porous feature underlying the surface of the mold 830.With the added structural strength provided by a honeycomb or mesh, thelayer 834 may be broken or punctured and still allow of the passage ofthe air but the mold 830 may have the structural resilience to withstandthe pressures generated by the shell formation upon the mold 830surface.

FIG. 35 illustrates a flow diagram for removing the oral appliancefabricated upon a mold, as described above. As previously described, thedigital model of the lower and upper arches may be loaded into thecomputer system 840. The system may then identify an appropriate areaalong the model for tool insertion 842. Such an area may be located awayfrom the dentition model and so as not to interfere with the fabricationof the oral appliance upon the mold. The system may trim the model bydefining a through-hole from insertion 844 and to strengthen thethrough-hole, the system may then remodel the hole area by forming theregion of the hole adjacent to where the dentition is modeled as a meshor honeycomb configuration 846 to provide strength to the model whenfabricated but which still allows for air to pass through the openingsdefined by the mesh or honeycomb. The model may incorporate a receivingfixture to allow for the insertion of tools and/or allows for thesecurement of the mold during removal of the oral appliance from themold 848. Once the model has been completed, a 3D printer acceptablemodel may be exported 850.

FIG. 36 shows yet another exemplary embodiment for facilitating removalof the fabricated oral appliance from the mold in the end view of mold860. The mold 860 may be formed to define an opening or channel 862which extends through the mold 860 from a bottom (e.g., opposite to theportion of the mold replicating the dentition) towards a top (e.g.,portion of the mold replicating the dentition such as the occlusalsurfaces). In this embodiment, a tapered structure 864 may be formed tobe part of the oral appliance 872 which is formed upon the mold 860. Thetapered structure 864 may remain attached to an internal surface of theoral appliance while being formed with a tapered surface 866 whichtapers to a larger diameter structure within the opening or channel 862away from the oral appliance 872.

The tapered structure 864, once formed, may present a cork-likestructure which helps to secure the oral appliance upon the mold 860during fabrication and processing. Once the oral appliance 872 iscompleted and ready for release and removal from the mold 860, a toolmay be inserted into the opening or channel 862, in the direction 870 asindicated, and used to gently push against the bottom surface of thetapered structure 864 to urge the release of the oral appliance 872 fromthe mold 860 until the tapered structure 864 is removed entirely fromthe opening or channel 862, in the direction 868 as indicated. Once theoral appliance 872 has been removed entirely, the tapered structure 864may be removed from the oral appliance 872 as well.

FIG. 37 illustrates a flow diagram for removing the oral appliancefabricated upon a mold using the tapered structure 864, as describedabove. As previously described, the digital model of the lower and upperarches may be loaded into the computer system 880. The system may thenidentify an appropriate area along the model for tool insertion 882.Such an area may be located away from the dentition model and so as notto interfere with the fabrication of the oral appliance upon the mold.The system may trim the model by defining a through-hole from insertion884 and to strengthen the through-hole, the system may then remodel thehole area by forming or inserting the tapered structure 864 (e.g.,reverse cork-type structure) 886. The model may incorporate a receivingfixture to allow for the insertion of tools and/or allows for thesecurement of the mold during removal 888 of the oral appliance from themold. Once the model has been completed, a 3D printer acceptable modelmay be exported 890.

The system or method described herein may be deployed in part or inwhole through a computer system or machine having one or more processorsthat execute software programs with the methods as described herein. Thesoftware programs may be executed on computer systems such as a server,domain server, Internet server, intranet server, and other variants suchas secondary server, host server, distributed server, or other suchcomputer or networking hardware on a processor. The processor may be apart of a server, client, network infrastructure, mobile computingplatform, stationary computing platform, or other computing platform.The processor may be any kind of computational or processing devicecapable of executing program instructions, codes, binary instructions orthe like that may directly or indirectly facilitate execution of programcode or program instructions stored thereon. In addition, other devicesrequired for execution of methods as described in this application maybe considered as a part of the infrastructure associated with thecomputer system or server.

The system or method described herein may be deployed in part or inwhole through network infrastructures. The network infrastructure mayinclude elements such as computing devices, servers, routers, hubs,firewalls, clients, wireless communication devices, personal computers,communication devices, routing devices, and other active and passivedevices, modules or components as known in the art. The computing ornon-computing device(s) associated with the network infrastructure mayinclude, apart from other components, a storage medium such as flashmemory, buffer, stack, RAM, ROM, or the like. The processes, methods,program codes, and instructions described herein and elsewhere may beexecuted by the one or more network infrastructural elements.

The elements described and depicted herein, including flow charts,sequence diagrams, and other diagrams throughout the figures, implylogical boundaries between the elements. However, according to softwareor hardware engineering practices, the depicted elements and thefunctions thereof may be implemented on machines through the computerexecutable media having a processor capable of executing programinstructions stored thereon and all such implementations may be withinthe scope of this document. Thus, while the foregoing drawings anddescriptions set forth functional aspects of the disclosed methods, noparticular arrangement of software for implementing these functionalaspects should be inferred from these descriptions unless explicitlystated or otherwise clear from the context. Similarly, it will beappreciated that the various steps identified and described above may bevaried, and that the order of steps may be adapted to particularapplications of the techniques disclosed herein. All such variations andmodifications are intended to fall within the scope of this document. Assuch, the depiction or description of an order for various steps shouldnot be understood to require a particular order of execution for thosesteps, unless required by a particular application, or explicitly statedor otherwise clear from the context.

Thus, in one aspect, each method described above and combinationsthereof may be embodied in computer executable code that, when executingon one or more computing devices, performs the steps thereof. In anotheraspect, the methods may be embodied in systems that perform the stepsthereof, and may be distributed across devices in a number of ways, orall of the functionality may be integrated into a dedicated, standalonedevice, or other hardware. All such permutations and combinations areintended to fall within the scope of the present disclosure.

The applications of the devices and methods discussed above are notlimited to the dental applications but may include any number of furthertreatment applications. Moreover, such devices and methods may beapplied to other treatment sites within the body. Modification of theabove-described assemblies and methods for carrying out the invention,combinations between different variations as practicable, and variationsof aspects of the invention that are obvious to those of skill in theart are intended to be within the scope of the claims.

What is claimed is:
 1. A method for treating a subject, comprising:receiving a scanned dental model of a subject's dentition; determining atreatment plan having a plurality of incremental movements forrepositioning one or more teeth of the subject's dentition, wherein oneor more three-dimensional spheres of influence each having a predefineddiameter is assigned to a model of each of the one or more teeth todefine a safety envelope and to set a proximity distance between eachtooth model as the tooth models move along a tooth movement path; anddisplaying the tooth movement path of each tooth model.
 2. The method ofclaim 1 further comprising reassessing the subject's dentition after apredetermined period of time to monitor the repositioning of the one ormore teeth.
 3. The method of claim 1 further comprising fabricating oneor more aligners correlating to a first subset of the plurality ofincremental movements.
 4. The method of claim 3 further comprisingfabricating one or more additional aligners correlating to a secondsubset of the plurality of incremental movements.
 5. The method of claim3 further comprising treating the one or more teeth via a non-alignercorrective measure.
 6. The method of claim 1 wherein receiving a scanneddental model comprises receiving a digital image of the subject'sdentition.
 7. The method of claim 1 wherein determining a treatment planfurther comprises: applying a label to one or more teeth within thedental model; simulating a rolling ball process along an exterior of theone or more teeth and gums within the dental model; determining aboundary between each of the one or more teeth and gums based on a pathor trajectory of the rolling ball process; assigning a hard or softregion to each of the one or more teeth and gums within the dentalmodel; and moving a position of the one or more teeth within the dentalmodel to correct for malocclusions in developing a treatment plan. 8.The method of claim 7 wherein simulating a rolling ball processcomprises detecting for changes in a path of the rolling ball.
 9. Themethod of claim 7 wherein determining a boundary comprises determining aboundary between adjacent teeth based on a projected trajectory of therolling ball between the teeth.
 10. The method of claim 1 whereindetermining a treatment plan further comprises: determining a movementfor a plurality of digital tooth models in the dental model forcorrecting the malocclusions via a tooth movement manager module;assigning the spheres of influence on each of the tooth models via acollision manager module; monitoring an actual state of each tooth ofthe subject; comparing the actual state of each tooth against anexpected state of each tooth model via a tooth manager module; andadjusting the movement of one or more teeth based on a comparison of theactual state and the expected state if a deviation is detected.
 11. Themethod of claim 10 wherein determining a movement comprisesindependently executing a tooth movement plan for each of the toothmodels.
 12. The method of claim 10 wherein assigning a sphere ofinfluence further comprises monitoring for a collision between toothmodels.
 13. The method of claim 12 further comprising communicating acollision warning to an adjacent tooth model such that one or more ofthe tooth models alter their movement to avoid the collision.
 14. Themethod of claim 1 wherein fabricating one or more aligners furthercomprises: fabricating a support structure which corresponds to an outersurface of the dentition; forming one or more oral appliances upon anexterior surface of the support structure such that an interior of theone or more oral appliances conform to the dentition; and removing thesupport structure from the interior of the one or more oral appliances.15. The method of claim 14 wherein forming one or more oral appliancescomprises forming one or more dental attachments upon the oralappliances.
 16. The method of claim 1 wherein fabricating one or morealigners further comprises: calculating a rule-based cutting loop pathon the model for determining a path for trimming a mold replicating thepatient's dentition; applying a drape wall from the cutting loop on themodel to reduce a complexity of the model; determining a position of acutting instrument relative to the mold for trimming the mold;generating a computer numerical control code based on the drape wall andposition of the cutting instrument; and fabricating the mold based onthe generated computer numerical control code.
 17. The method of claim16 wherein calculating a rule-based cutting loop path comprisesidentifying a first location and a second location opposite to the firstlocation on the model at corresponding interface regions and extending atrim line between the first location and second location.
 18. The methodof claim 17 wherein applying a drape wall comprises identifying the trimline and replacing a volume below the trim line with a base region. 19.The method of claim 16 wherein applying a drape wall comprises limitinga height of the drape wall to avoid stretching an oral appliance formedupon the mold.
 20. The method of claim 16 wherein fabricating the moldcomprises securing the mold to a platform.